JPS5533069A - Semiconductor device - Google Patents

Abstract

PURPOSE: To increase the current capacity of a semiconductor device by providing an N-type buried layer under the inverted layer direclty under the gate insulated film of a P-type substrate to be connected to a drain layer and connecting a source layer to one end of the inverted layer to thereby form a stereoscopic channel.

CONSTITUTION: After As ion is implanted through a resist mask 13 in a depth of 6,000Å on a P-type silicon substrate 1 to form an N⁺ type layer 7 and to then remove the resist, a field oxide film 6 is formed with Si₃N₄ mask. At this time the layer 7 is activated. Then B ion injection layer 14 is formed in a depth of approx. 1,000Å from the surface and returned to the same conductivity type as the substrate to thereby compensate the N⁺ type buried layer end to thus obtain desired threshold voltage thereat. Then, a gate oxide film 2 and poly-silicon gate electrode 3 are formed, N⁺ type source 4 and drain 5 are formed to make the electrode 3 conductive. Then it is coated with PSG 11 to thus form an electrode 12. Since this structure provides three-dimensional conductive state of channel, it increases the current capacity not to concentrate the electric field at the drain end under the gate to thereby provide high dielectricity.

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