A trench is formed on the surface of a semiconductor substrate. An oxide film is then formed on the side wall portion and the bottom portion of the trench, ions are implanted at least in the side wall portion of the trench for preventing an impurity from passing through there. Thereafter the ion-implanted...http://www.google.com.au/patents/US5943589?utm_source=gb-gplus-sharePatent US5943589 - Method of fabricating semiconductor device with a trench isolation
