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US 4,049,478 AGranted
Utilization of an arsenic diffused emitter in the fabrication of a high performance semiconductor device
AssigneeIBM Corporation
InventorsHitendra N. Ghosh, Madhukar L. Joshi, Tsu-Hsing Yeh
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Abstract
A substantially square N-type impurity distribution profile in a silicon substrate produces much superior dc and ac characteristics in PN junction devices than can be expected from the usual phosphorus distribution profile. Such a square profile is obtained by diffusion of arsenic in the silicon substrate. The sharper impurity gradient allows a relatively low surface concentration to be used for the device. This lower surface concentration relieves precipitation and dislocation problems.
Claims4
The mehtod of forming a high performance PN semiconductor device comprising:
- introducing a P-type impurity into a silicon semi-conductor body so as to provide a surface concentration level of greater than about 10.sup.19 atoms per cm.sup.3 ;
- diffusing arsenic within said P-type region so as to provide a surface concentration level of arsenic of greater than about 10.sup.20 per cm.sup.3 ;
- continuing said diffusion step until said arsenic forms a substantially square impurity distribution.
Dependencies are inferred from the claim text.