WO2015167495A1

WO2015167495A1 - Printhead with an off-chip memristor assembly

Info

Publication number: WO2015167495A1
Application number: PCT/US2014/036053
Authority: WO
Inventors: Ning GE; Jianhua Yang; Zhiyong Li; Max ZHANG
Original assignee: Hewlett-Packard Development Company, L.P.
Priority date: 2014-04-30
Filing date: 2014-04-30
Publication date: 2015-11-05

Abstract

A printhead with an off-chip memristor assembly is described. The printhead includes a nozzle, a firing chamber to hold an amount of fluid, and an ejector to eject the amount of fluid through the nozzle. The printhead also includes an off-chip memristor assembly. The off-chip memristor assembly includes a bottom electrode. A number of switching oxides extend from the bottom electrode. A number of top electrodes extend from the number of switching oxides to align with a number of bonding pads on an integrated circuit. A portion of the bottom electrode, a switching oxide and a top electrode form a memristor device. The bottom electrode is a common ground for a number of memristor devices.

Description

PRINTHEAD WITH AH OFF-CHIP MEM iSTO ASSEMBLY

BACKGROUND

[OOOI3 A memory assembly may be used to store data, in some examples, printing devices such as priniheads may include memory to store information relating to ink supplies, ink identification, ink characterization, ink usage, among other types of data.

BRIEF DESCRIPTION OF THE DRAWI GS

[0002] The accompanying drawings illustrate various examples of the principles described herein and are a part of the specification. The illustrated examples do not limit the scope of the claims.

[0003] Fig. 1 is a diagram of a printer cartridge and printhead with an off-chip memristor assembly according to one example of the principles described herein.

[0004] Fig. 2 is a block diagram of a printer cartridge that uses a printhead with an off-chip memristor assembly according to one example of the principles described herein,

[00053 Fig, 3 is a side view of an off-chip memristor assembly according to one example of the principles described herein.

[0006] Fig. 4 is a perspective view of a memristor device of a memristor assembly according to one example of the principles described herein.

[00073 Fig. 5 is a top view of an off-chip memristor assembly according to one example of the principles described herein. [0008] Fig. 6 is a side view of an off-chip memristor assembly and an integrated circuit according to one example of the principles described herein,

[0009] Throughout the drawings, identical reference numbers designate similar, but not necessarily identical, elements,

DETAILED DESCRiPTiON

[0010] Printer cartridges include memory to store information reiated to the operation of the printhead. For exam pie, a printhead may inciude memory to store information related to the printhead, fluid, such as ink, used by the printhead, or other information relating to the use and maintenance of the printhead. More specifically, memory on printheads may be used to store information such as information relating to a fluid suppiy, fluid identification information, fluid characterization information, fluid usage data, among other types of fluid or imaging device reiated data. While memory usage on printheads is desirable, changing circumstances may reduce their efficacy in storing information.

[0011] For example, increased consumer usage and increased printe cartridge capabilities lead to a desire for greater amounts of data storage. Moreover, as new technologies develop, circuit space is at a premium.

Accordingly, it may be desirable for the greater amounts of data storage to occupy less space within a device. Memristors may be used due to their non- volatility, low operational power consumption characteristics, and thei compact size. Memristors may be incorporated onto a silicon wafer during a back end of the line (BEOL) process that occurs at the end of fabrication of an integrated circuit. Such back end of the line {BEOL) processes may be expensive, specialized, and time-intensive.

[0012] Accordingly, the present disclosure describes printer cartridge and a printhead with an off-chip memristor assembly that utilize a low cost non- silicon process. For example, a memristor assembly may be formed on an electroplated substrate, such as a printhead orifice plate. The memristor assembly, along with the orifice plate may then be attached to an integrated circuit via a bonding process. While the present specification describes an example where a memnstor assembly is used on a printhead, the off-chip memristor assembly as described herein may be used as an embedded memory device for an type of system thai uses such memory function as described herein.

[0013] The present disclosure describes a printhead with an off-chip memristor assembly. The printhead includes a nozzle, a firing chamber to hold an amount of fluid, and an ejector to eject the amount of fluid through the nozzle. The printhead aiso includes an off-chip memristor assembly. The off- chip memristor assembly may include a bottom electrode and a number of switching oxides extending from the bottom electrode. The memristor assembiy may aiso include a number of top electrodes extending from the number of switching oxides to align with a number of bonding pads on an integrated circuit. A portion of the bottom electrode, a switching oxide, and a top electrode may form a memristor device. The bottom electrode may be a common ground for a number of memristor devices.

[0014] The present disclosure describes a printer cartridge with an off-chip memristor assembly. The cartridge includes a fluid supply and a printhead to deposit the fluid from the fluid supply onto a surface. The printhead includes a bottom electrode and a number of switching oxides protruding from the bottom electrode. The off-chip memristor assembly may also include a number of top electrodes extending from the number of switching oxides to align with a number of bonding pads on an integrated circuit, A portion of the bottom electrode, a switching oxide, and a fop electrode may form a memristor device. The printer cartridge may also include an integrated circuit that includes a number of bonding pads to attach the integrated circuit to the off-chip memristor assembly via the number of top electrodes.

[00153 A printer cartridge and printhead as described in the present disclosure may be beneficial in that if provides for a dense, fast, non-volatile, and low energ memory device for use on an imaging system. The off-chip memristor assembly may be manufactured independently from an integrated circuit and may be attached at a later point in time. Such independent manufacture may reduce the cost associated with printhead fabrication.

[0016] As used in the present specification d in the appended claims, the term "printer cartridge" may refer to a device used in the ejection of ink, or other fluid, onto a print medium, in genera!, a printer cartridge may be a fluidic ejection device that dispenses fiuid such as ink, wax, polymers or other fluids. A printer cartridge may include a printhead. In some examples, a printhead may be used in printers, graphic plotters, copiers and facsimile machines, in these examples, a printhead may eject ink, or another fluid, onto a medium such as paper to form a desired image or a desired three-dimensiona! geometry.

[0017] Further, as used in the present specification and in the appended ciaims, the term "off-chip" may indicate that a particular eiement, such as a memristor, is not integrally formed with an integrated circuit or silicon wafer.

[0018] Stili further, as used in the present specification and in the appended claims, the term "memristor"^' may refer to a passive two-terminal circuit element that maintains a functional relationship between the time integral of current, and the time integral of voltage.

[0019} Sti!i further as used in the present specification and in the appended claims, the term "a number of or similar language may include any positive number including 1 to infinity; zero not being a number, but the absence of a number.

[0020] In the following description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough

understanding of the present systems and methods. It will be apparent, however, to one skilled in the art that the present apparatus, systems, and methods may be practiced without these specific details. Reference in the specification to "an example" or similar language means that a particular feature, structure, or characteristic described is included in at least that one example, but not necessarily in other exampies. [0021] Turning now to the figures, Fig. 1 is a diagram of a printer cartridge (100) and printhead (101) with an off-chip memrisior assembly according to one example of the principles described herein. The printer cartridge {100} may include a printhead (101) to carry out at least a part of the functionality of depositing fluid onto a surface. The printer cartridge (100) may include a fluid supply (119) for supplying the fluid to the printhead (101) for deposition onto a surface, in some examples, the fluid may be ink. For exam pie, tbe printer cartridge (100) may be an inkjet printer cartridge, t he printhead (101) may be an inkjet printhead, and the ink may be inkjet ink.

[0022] The printhead (101) may include a number of components for depositing a fluid onto a surface. For example, the printhead (101) may include an ejector (120), a firing chamber (121), and a nozzle (122). The nozzle (122) may be a component that includes a small opening through which fluid, such as ink, is deposited onto a surface, such as a print medium. The firing chamber (121) may include a smaii amount of fluid. The ejector (120) is a component that ejects fluid through the nozzle (122). For example, the ejector (120) may be a firing resisior that heats up in response to an applied voltage. As tbe firing resisior heats up, a portion of the fluid in the firing chamber (121) vaporizes to form a bubble. This bubble pushes liquid fluid out the nozzle (122) and onto the surface. As the vaporized fluid bubble pops, a vacuum pressure within the firing chamber (121) draws fluid into the firing chamber (121) from the fluid supply (119), and the process repeats.

[0023] The printhead (101) and printer cartridge (100) may also include other components to carry out various functions related to printing. For simplicity, in Fig. 1, a number of these components and circuitry included in the printhead (101) and printer cartridge (100) are not indicated; however such components may be present in the printhead (101) and printer cartridge (100), In some examples, the printer cartridge (100) is a disposable printer cartridge. The printhead (101) may of varying types. For example, the printhead (101) may be a thermal inkjet (TIJ) printhead or a piezoelectric inkjet (PIJ) printhead, among other types of printhead ( 01). As used herein, and in the appended claims, an "ejector'' is a mechanism for ejecting fluid through a nozzle from a firing chamber (121), where the ejector (120) may include a firing resistor or other thermal device, a piezoelectric element, or other mechanism for ejecting fluid from the firing chamber (121).

[0024] Fig. 2 is a block diagram of a printer cartridge (200) printer cartridge that uses a printhead (201) with an off-chip memristor assembly (202) according to one example of the principles described herein. As used herein, an off-chip memristor assembly (202) is a collection of memristor devices that are independent of a silicon wafer, the silicon wafer including integrated circuits and other functional components of the system, in other words, the memristor devices may not be integrally formed with such a silicon wafer. For example, the memristor assembly (202) may be formed on an orifice piate of a printer.

[0025] The printer cartridge (200) may be in communication with a controiiing device such that the controiling device sends instructions to the printer cartridge (200). For example, a controiiing device may send a print job to the printer cartridge (200), the print job being made up of text, images, or combinations thereof to be printed. In use, the printer cartridge (200) includes a number of components for carrying out the operations of the printer cartridge (200).

[0026] The printer cartridge (200) may include a printhead (201 ). The printhead (201} may carry out at least a part of the functionality of the printer cartridge (200). The printhead (201) may include a number of printhead dies and a number of nozzles (Fig. 1 , 122). The printhead dies may eject drops of fluid from the nozzles (Fig. 1 , 122) onto a print medium in accordanc with a received print job. More specifically, the printhead (201) ma include a thin metallic piece of material to form a firing chamber (Fig. 1, 121) of an inkjet printer system. This thin metallic piece of material may be referred to as an orifice plate, in some examples, the orifice plate may be between 20 and 40 micrometers thick. In some examples, the orifice piate may be 100 micrometers thick.

[0027] The printhead (201) may include a memristor assembly (202) to store information relating to at least one of the printer cartridge (200) and the printhead (201 ). in some examples, the memristor assembly (202) may include a number of memristor devices formed in the printhead (201). For exam pie. as will e described in detaii beiow, the memristor devices may be formed on top of an electro-plated substrate. The memristor assembly (202) may be used to store any type of data. Examples of data that may be stored in the memristor assembly (202) that is formed in a printhead (201) include fluid suppiy specific data and/or fluid identification data, fluid characterization data, fluid usage data, printhead (201) specific data, printhead (201) identification data, warranty data, printhead (201) characterization data, printhead (201) usage data, authentication data, security data, Anti-Counterfeits ng data (ACF), fluid drop weight, firing frequency, initial printing position, acceleration information, and gyro information, among other forms of data, in a number of examples, the memristor assembly (202) may be written at the time of manufacturing and/or during the operation of the printer cartridge (200),

[0028] The printer cartridge (200) may also include a controller (203) to receive data from the controlling device and to send the data (204) onto the printhead (201). For example, the controller (203) may send data (204) such as autheniication data, security data, and print job data, in addition to other types of data (204} to the printhead (201) to be stored on the memristor assembly (202).

[0029] Fig. 3 is a side view of an off-chip memristo assembly (302) according to one example of the principles described herein. The off-chip memristor assembly (302) may be used in a printhead (Fig. 1, 101). in some examples, the memristor assembly (302) includes a bottom electrode (305). As wiii be described in detail beiow, the bottom electrode (305) may be shared by the memristor devices (311) of the memristor assembly (302) and may be a common ground for a number of memristor devices (311 ). The bottom electrode (305) may be a substrate that provides mechanical stability to the memristor assembly (302) as well as an electrical connection between the memristor assembly (302) and other components that may attach to the bottom electrode (305). Examples of other components that attach to the bottom electrode (305) include a ground connection, a number of connection pads, a current regulator, a capacitor, a resistor, and metal traces, among other memristor assembly (302) components.

[0030] in some examples, the bottom electrode (305) includes a substrate (310). The substrate (310) may be metallic. For example, the substrate (310) may be nickel. More specifically, the substrate (310) may be an electroplated substrate. For example, a base may be subject to a physical vapor deposition process to sputter on a Iayer of metallic substances such as stainless steel and chrome. The base may be constructed of glass, silicon, or other base iayer material that wouid provide mechanical rigidity to the memristor assembly (302). If the base is constructed out of glass or silicon, the thickness of the substrate may be between 200 and 600 micrometers thick.

[0031] In some examples, the substrate (3 0) may include a coating material (306). For example, after the glass base has been

electroplated, a iayer of another metallic substance may be deposited on the substrate (310). The metallic substance may be conductive. Examples of this coating material (306) include, but are not limited to palladium, gold, tantalum, rhodium, copper, platinum, titanium nitride, and tantalum nitride among other coating materials. The coating material (306) may change the resistivity of the bottom electrode (305). In some examples, the bottom electrode (305) is an orifice plate that is used to eject ink from a thermal inkjet printer.

[0032] The memristor assembly (302) also includes a number of switching oxides (307) extending from the bottom electrode (305). For example, the number of switching oxides (307) may extend perpendicular to a surface of the bottom electrode (305). The switching oxide (307) is an insulator between the bottom electrode (305) and the top electrodes (308). For example, in a first form, the switching oxide (307) may have nominal insulation, and then during a switching event, the switching oxide (307) may switch to a second form, becoming conductive. In a conductive form, the switching oxide (307) allows the stat of the memristor devic to switch from a Sow resistive state to a high resistive state.

[0033] in some examples, the switching oxides (307) may be formed by oxidizing the coating material (306). For example, the switching oxides {307) may be formed by thermal oxidation, a process which exposes the coating materia! {306) to oxidizing agents at elevated temperatures. Specific examples of thermal oxidation processes thai may be used include a furnace oxidation process, a rapid thermal process, a rapid thermal oxidation, and a rapid thermal annealing, among other oxidation processes. In some examples, the switching oxides (307) are formed by performing piasma oxidation, which exposes the coating materials (308) to oxygen piasma at controlled

temperatures,

[0034] in another exampie, the switching oxides (307) are formed through a physicaS vapor deposition process wherein atoms or molecuies may be ejected from a target material to the conducting material {306). For example, a target materiai is bombarded with energetic particles, in response, atoms or molecules of the target material are dislodged and built up to form the switching oxides (307). While specific examples of switching oxide (307) formation processes have been given, other oxide forming processes are also

contemplated by the present specification. In some examples, the switching oxides (307) may have a thickness of between about, a few nanometers to a dozen nanometers.

[00351 in some examples, the switching oxides (307) may be magnesium oxide, titanium oxide, zirconium oxide, hafnium oxide, vanadium oxide, niobium oxide, tantalum oxide, chromium oxide, molybdenum oxide, tungsten oxide, manganese oxide, iron oxide, cobait oxide, copper oxide, zinc oxide, aluminum oxide, gallium oxide, silicon oxide, germanium oxide, tin dioxide, bismuth oxide, nickel oxide, yttrium oxide, gadolinium oxide, and rhenium oxide, among other oxides. In addition to the binary oxides presented, the switching oxides (307) may be ternary and complex oxides such as silicon oxyniiride. The oxides presented may be formed using a number of different processes such as sputtering from an oxide target or oxidizing a deposited metal or alloy layer.

[0036] The mem istor assembly (302) may aiso include a number of top electrodes (308) extending from the number of switching oxides (307). For exampie, as described above, the number of switching oxides (307) may extend perpendicular from the bottom electrode (305). The top electrodes (308) may aiso be perpendicular to the bottom electrode (305) and may extend from the switching oxides (307), In this example, each switching oxide (307) may have a corresponding top electrode (308) extending therefrom. In some examples, the top electrodes (308) may be formed from a metallic material such as tantalum or a tantalum-aluminum alloy, or other conducting material such as titanium, titanium nitride, copper, aluminum, and gold among other metallic materials.

[0037] A number of processes may be used to form the top electrodes (308), For example, the top electrodes (308) may be formed by a metallic deposition process such as physical vapor deposition (PVD), in which a target material is vaporized, meaning atoms are dislodged from the surface of the target material. The atoms are then built up on a surface. More specifically, atoms of the target material may be built up on the surface of the switching oxides (307) to form the top electrodes (308). While specific reference is made to PVD, other processes may be used to form the fop electrodes (308).

Examples of such processes include a lift-off process and shadow masking deposition, among other processes. The top electrodes (208) may then be further altered via a number of processes including photolithography, lithography, and etching, among other surface altering processes.

[0038] As described above, the memnstor assembly (302) may include a number of memristor devices (311) that are formed of the above described components. For example, a single memristor device (311), indicated by the dashed line, may include a portion of the bottom electrode (30S), a first switching oxide (307-1) and a corresponding top electrode (308-1), A number of other memristor devices (311) may also be formed from the bottom electrode (305) and the remaining switching oxides (307-2, 307-3) and top electrodes (308-3). While Fig. 3 depicts a memristor assembly (302) with three memristor devices (311), corresponding to the three switching oxides (307-1, 307-2, 307-3) and the three corresponding top electrodes (308-1, 308-2, 308-3), a memristor assembly (302) may include any number of memristor devices (311) as defined by the number of switching oxides (307) and top electrodes (308),

[0039] In some examples, the memristor assembly (302) may include a dielectric material {309} deposited on the bottom electrode (305). The dielectric material (309) may insulate the conduction of electrical signals between the bottom electrode (305) and the number of top electrodes (308). I some examples, the dielectric materia! (309) may be silicon dioxide, silicon nitride, or silicon carbide, among other dielectrics.

[00403 Fig, 4 is a perspective view of a memristor device (41 ) of a memristor assembly (Fig. 2, 202) according to one example of the principles described herein. As described above, the memristor assembly (Fig. 2, 202) includes a bottom electrode (405). The bottom electrode (405) may be shared by a number of memristor devices (411). The memristor assembly (Fig, 2, 202} also includes a number of switching oxides (407) protruding from the bottom electrode (405) and a number of top electrodes (408) extending from, and in line with, the number of switching oxides (407). For simplicity, Fig. 4 deposits a single switching oxide (407) and a single top electrode (408), However, as depicted in Fig, 3, a memristor assembly (Fig. 3, 302) may include a number of switching oxides (407) and a corresponding number of top electrodes (408),

[0041] Each memristor device (411), while sharing a bottom electrode (405) may have a switching oxide (407) and a top electrode (408} that are distinct from the switching oxides (not shown) and top electrodes (not shown) of the other memristor devices (not shown). In other words, in this example, a portion of the bottom electrode (405), a switching electrode (407), and a top electrode (408) form a single memristor device (41 }. While one memristor device (411 ) is indicated in Fig. 4, similar devices are formed by the bottom electrode (405) and the switching oxides (Fig. 3, 307-1 , 307-2, 307-3) and the top electrodes (Fig. 3, 308-1 , 308-2, 308-3), In other words, each distinct memristor device (411) includes a distinct switching oxide (407} and a corresponding top electrode (408), while sharing a common bottom electrode (405) with other memristor devices (411). [0042] The memristor device (411) may be a non-voiatile memory device thai retains stored information even when not powered on. The memristor device (411) may seiectiveiy store data based on a resistive state of the memristor. For example, the memristor device (411) may be in a !ow resistive state indicated by a "1," or a high resistive state indicated by a "0." The memristor devices (411) of the memristor assembly (Fig. 2, 202) may form a string of ones and zeroes that will store the aforementioned data. If an analog memristor device (411) is used, there may be many different resistive states.

[00433 Fig, 5 is a top view of an off-chip memristor assembly (502) according to one example of the principles described herein. As described above, the memristor assembly (502) may include a shared bottom electrode (505) that forms part of each memristor device (Fig. 4, 411) of th memristor assembly (502). Similarly, each memristor device may include a distinct switching oxide (Fig. 3, 307) extending from the bottom electrode (505) up and perpendicular to the surface of the bottom electrode (505). Disposed on each switching oxide (Fig. 3, 307) is a top electrode (508). As described above, a memristor device (Fig. 4, 4 1) includes a distinct top electrode (508) and a distinct switching oxide (Fig. 3, 307) that corresponds to the distinct top electrode (508). Accordingly, as Fig. 5 depicts nine distinct top electrodes (508- 1, 508-2, 508-3, 508-4, 508-5, 508-6, 508-7, 508-8, 508-9), the memristor assembly (502) of Fig. 5 may include nine distinct memristor devices (Fig. 4, 411), As indicated in Fig. 5, the memristor devices {Fig. 4, 411) may be arranged as rows and columns. Whiie Fig. 5 depicts nine top electrodes (508), and as a result nine memristor devices {Fig. 4, 411), a memristor assembly (502) may include any number of memristor devices (Fig. 4, 411) and top electrodes (508).

[0044] Fig. 6 is a side view of an off-chip memristor assembly (602) and an integrated circuit (612) according to one example of the principles described herein. As demonstrated above, the memristor assembly (602) may include a bottom electrode (605) that is shared by each memristor device (Fig. 3, 311), a number of switching oxides (not shown), a number of top electrodes (608) and a dielectric material (609). The number of top electrodes (608) may attach to a number of bonding pads (613) found on the integrated circuit (612). For example, a first memristor device (Fig, 3, 311), via the first top electrode (608-1), may attach to the integrated circuit (612) via a first bonding pad (613-1) using a bonding process. Similarly, a second memrisior device (Fig. 3, 311), via the second top electrode (608-2), may attach to the integrated circuit (612) via a second bonding pad (613-2) using a bonding process. Similarly, a third memristor device {Fig, 3, 311), via the third top electrode (608-3), may attach to the integrated circuit (612) via a third bonding pad (613-3) using a bonding process.

[0045] A number of bonding processes may be used to attach the memrisio assembly (602) to the integrated circuit (612). For example, a gang bonding process may be used. Accordingly, the top electrode (608) material and the bonding pad (613) material may be chosen to facilitate the bonding process. For example, the top electrodes (608) and the bonding pads (613) may be formed of gold to facilitate a gold-goid bonding process. Other examples of bonding processes by which the memristor devices {Fig 3, 311) are attached to the bonding pads (613} may include conductive adhesive bonding, and plasma-enhanced bonding, among other bonding techniques. In some examples, the integrated circuit may be a pre-fabricated silicon die that includes other transistors and capacitors thai may have been attached during front end of the line {FEOL} processes or back end of the Sine {8EOL} processes.

[0048] in some examples, the memristor assembly (602) may be designed to form a one-to-one addressing structure with the integrated circuit (612). For example, an integrated circuit (612) may include a number of addressing units (614). Each addressing unit (614) may include a number of components that allow for multiplexing and logic operations. For example, a first addressing unit (614-1) may include a source (615-1), a gate (616-1), and a drain (617-1). For simplicity, one source (615-1), gate (616-1), and drain {817- 1) are indicated by a reference numeral, but other addressing units (614-2, 614- 3) contain similar elements.

[0047} The memristor devices {Fig. 3, 311) may be designed to be individually addressed by a distinct addressing unit (614). For example, the memristor device (Fig. 3, 311} that corresponds to ihe first top electrode (808-1) may have a corresponding first addressing unit (614-1) of the integrated circuit

(612) , Similarly, the rnernristor device (Fig, 3, 311) that corresponds to the second top electrode (608-2) may have a corresponding second addressing unit (614-2) in the integrated circuit (612). Similarly, the memristor device (Fig. 3,

311 ) that corresponds to the third top electrode (808-3) may have a

corresponding third addressing unit (614-3) in the integrated circuit (612).

[0048] in some examples, the addressing units (614) may be transistors. In this example, the memristor devices (Fig. 3, 311 ) may share a one-transistor one-memristor (1T1 ) addressing structure with the addressing units (614) of the integrated circuit (612). In another example, the addressing units may be diodes. In this example, the memristor devices (Fig. 3, 31 1 ) may share a one-diode one-memristor (1 D1 ) addressing structure with the addressing units (614) of the integrated circuit (612).

[0049] in some examples the number of memristor devices (Fig. 3, 311) on a memristor assembly (602) may be less than the number of bond pads

(613) on an integrated circuit (612). Accordingly, in this example, a number of memristor assemblies (602) may be bonded to the integrated circuit (612} via different groupings of different bond pads (613).

[0050] The integrated circuit (612) may include other elements, such as a contact (618) to connect an addressing unit (614) to a bonding pad (613). For simplicity, a single contact (618) is indicated in Fig. 6. The integrated circuit (612) may also include an inter-layer dielectric (619) to isolate a substrate of the integrated circuit (612) from the bonding pads (613).

[0051] In summary, the present specification allows for a base, such as an orifice plate, to be formed via an electroplating process. A number of switching oxides (Fig. 3, 307} may be formed on the base and a number of top electrodes (Fig. 3, 308) may then be formed on the switching oxides (Fig. 3, 307); a portion of the orifice piate, a switching oxide (Fig. 3, 307), and a top electrode (Fig. 3, 308) making up a memristor device (Fig. 3, 311). The orifice plate with memristor assembly (Fig. 2, 202) may then be attached to a pre- fabricated Silicon integrated circuit or other flexible circuit for use in a printhead (Fig. 1 , 101 ).

[0052] A printer cartridge (Fig. 1, 100} and a printhead (Fig, 1 101) with an off-chip memristor assembly (Fig. 1 , 102) may have a number of advantages, including: (1 ) de-coupiing memristor manufacturing and integrated circuit manufacturing; (2) allowing flexibility for FEOL and BEOL processes; (3) simplifying manufacturing processes; (4) allowing for cost control in printer memory device manufacturing; (5) increasing storage capacity of memory used on a printhead in a reduced space; and (6) improving printhead memory performance.

[0053] The preceding description has been presented to iiiustrate and describe examples of the principles described. This description is not intended to be exhaustive or to limit these principles to any precise form disclosed. Many modifications and variations are possible in light of the above teaching.

Claims

CLAIMS WHAT IS CLAIMED IS:

1. A printhead with an off-chip memrisior assembly, the pnnthead comprising:

a nozzle;

a firing chamber to hold an amount of fluid;

an ejector to eject the amount of fluid through the nozzle; and

an off-chip memristor assembly, the off-chip memristor assembly comprising;

a bottom electrode;

a number of switching oxides extending from the bottom electrode; and

a number of top electrodes extending from the number of switching oxides to align with a number of bonding pads on an integrated circuit;

in which a portion of the bottom electrode, a switching oxide, and a top electrode form a memristor device; and

in which the bottom electrode is a common ground for a number of memristor devices.

2. The printhead of claim 1 « in which the fluid is Inkjet ink,

3. The printhead of ciaim 1 , in which the bottom electrode is shared by each memristor device, and in which each memristor device comprises a distinct switching oxide and top electrode.

4. The printhead of ciaim 1, in which the bottom electrode comprises an electroplated substrate.

5. The printhead of claim 1 , in which the bottom electrode comprises an orifice plate,

8, The printhead of claim 1 , in which the number of switching oxides extend perpendicular to a surface of the bottom electrode and in which the number of top electrodes extend in line with the number of switching oxides.

7. The printhead of daim 1 , further comprising a coating material disposed on a number of su faces of the bottom electrode.

8. The printhead of claim 1. in which the off-chip memristor assembly is included in a printhead.

9. A printer cartridge with an off-chip memristor assembly, the cartridge comprising:

a fluid supply;

a printhead to deposit the fluid from the fluid supply onto a surface, the printhead com rising:

a bottom electrode;

a number of switching oxides protruding from the bottom eiectrode; and

a number of top electrodes extending from the number of switching oxides,

in which the bottom electrode, the number of switching oxides and the number of top electrodes form a number of memristor devices; and an integrated circuit comprising a number of bonding pads to attach the integrated circuit to the printhead via the top electrodes.

10. The cartridge of claim 9, in which:

the fluid is Inkjet ink;

the printer cartridge is an Inkjet printer cartridge; and

the printhead is an inkjet printhead.

11. The cartridge of claim 9, in which the integrated circuit further comprises a number of addressing units that correspond to the number of memristor devices,

12. The printer cartridge of claim 11, in which the number of memristor devices have a one-to-one structure with the number of addressing units on the integrated circuit..

13. The printer cartridge of claim 11, in which an addressing unit is a transistor.

14. The printer cartridge of claim 11, in which an addressing unit is a diode.

15. The printer cartridge of claim 11 , in which each addressing unit corresponds to a distinct memristor device.