The process comprises a sequence of steps initiated by forming a word line mask on the surface of a substrate of a first conductivity type. Ions are implanted to form word lines covered by a dielectric layer. A polysilicon layer doped with a given conductivity type on the dielectric layer is formed on...http://www.google.de/patents/US5378647?utm_source=gb-gplus-sharePatent US5378647 - Method of making a bottom gate mask ROM device
