A resonant tunneling diode (400) made of a germanium quantum well (406) with silicon oxide tunneling barriers (404, 408). The silicon oxide tunneling barriers (404, 408) plus germanium quantum well (406) may be fabricated by oxygen segregation from germanium oxides to silicon oxides....http://www.google.com.au/patents/US5466949?utm_source=gb-gplus-sharePatent US5466949 - Silicon oxide germanium resonant tunneling
