Browse Prior Art Database

Self Aligned Insulated Gate Field Effect Transistor

IP.com Disclosure Number: IPCOM000080006D
Original Publication Date: 1973-Oct-01
Included in the Prior Art Database: 2005-Feb-26
Document File: 2 page(s) / 51K

Publishing Venue

IBM

Related People

Esnault, J: AUTHOR [+2]

Abstract

A convenient solution to the problem of the correct alignment of both source and drain regions with respect to the gate region, thereby eliminating the parasitic capacitance between the gate and these regions due to the well-known overlap effect, is described below.

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Self Aligned Insulated Gate Field Effect Transistor

A convenient solution to the problem of the correct alignment of both source and drain regions with respect to the gate region, thereby eliminating the parasitic capacitance between the gate and these regions due to the well-known overlap effect, is described below.

The basic process may be described according to the drawing. A P-type silicon substrate 10 is coated with a 6000 angstroms silicon dioxide layer 11. Using standard photoengraving techniques, an opening 12 is provided through this oxide layer 11 and diffusion of a N-type dopant is made to form a N-type region 13. The diffusion depth is preferably about 1 micron. This first step is represented in Fig. A.

The substrate is then reoxidized to form a layer 14 of new silicon dioxide of about 6000 angstroms in the opening. A thin blanket layer of silicon nitride 15 is then deposited over the substrate 10 and an opening 16 is provided at the center of the previous diffused region 13, through the composite insulating layer 14-15. A P-type diffused region then is provided having a depth of about 1.5 microns, which separates the N-type region 13 in two discrete regions 13 A and 13 B, to respectively form the drain and the source regions of the insulated gate field- effect transistor (IGFET). The P-type region 17 will constitute the channel region (Fig. B).

Using the thin silicon nitride layer 15 as a mask, the underlying silicon dioxide layer 14 is etched, the l...