摘要 |
During the growth of an oxide on the surface of a P-type silicon semiconductor wafer, thermal oxidation of the semiconductor surface produces an N-channel region near the silicon/silicon dioxide interface by the conductivity inversion behavior, thereby establishing a PN junction barrier therebetween. By a photo-lithographic etching process, a heavily doped P-type diffusion region (that is, P+ region) operatively associated with the P-type semiconductor wafer, is disposed at the peripheral portion of the semiconductor wafer to surround the PN junction barrier and shield the same against the outside ambient atmosphere. Besides, a heavily doped N-type diffusion region (N+ region) is made up inside of the heavily doped P-type region in a manner to describe a closed loop. An electrode assembly includes metal contact layers having extensions over a dioxide which has been disposed between the P+ region and the N+ region during the fabrication procedure, so that the overlying electrode structure precludes the formation of an undesired N-channel region between the P+ and N+ diffusion regions.
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