Patent ID: 6420225
Filing Date: 2002-07-16
Classification: H01L

Abstract:
A method of fabricating a semiconductor rectifier device comprising the steps of;a) providing a semiconductor substrate of a first conductivity type and having opposing major surfaces, b) forming a first silicon oxide layer on a first major surface, e) forming a first doped polysilicon layer on the first silicon oxide layer, d) forming pedestals of silicon oxide on the first polysilicon layer as a dopant implant mask, e) implanting first ions of a second conductive type in the substrate using the pedestals as a mask, f) forming sidewall spacers on the pedestals, g) implanting second ions of the second conductive type deeper into the substrate than the first ions using the pedestals with sidewalls as a mask, h) removing the first polysilicon layer and the first silicon oxide layer exposed between pedestals and sidewall spacers to define gates under the pedestals and sidewall spacers, i) implanting third ions of the first conducting type into the substrate and shallower than the first ions using the pedestals with sidewalls as a mask, j) annealing the implanted ions to form doped regions, k) removing the pedestals and sidewall spacers, and l) forming conductive metal layers on the first major surface and on the second major surface.