Semiconductor device having a high breakdown voltage junction characteristic

Claim 1

A semiconductor device having a p-n junction characterized by low electric field crowding and a resulting high avalanche breakdown voltage requirement comprising: a semiconductor substrate having dopant impurity atoms of one type conductivity and a first surface; a first doped region in said substrate at said first surface and having dopant impurity atoms of a second type conductivity opposite to said one type conductivity of said substrate; a second doped region in said substrate at said first surface and having dopant impurity atoms of said second type conductivity but of less density than the dopant impurity atoms of said first doped region, said second doped region bounding the entire lateral perimeter of said first doped region in contiguous relation thereto and extending laterally outwardly from said first doped region along said first surface of said substrate; and said second doped region being depleted in response to the application of a reverse bias voltage to said first doped region to reduce electric field crowding along the depth-defining boundary of said first doped region, whereby the magnitude of the reverse bias voltage applied to said first doped region which is required to produce avalanche breakdown is increased.