Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
143 words
A field effect transistor comprising a semiconductor body region (10,12) of one conductivity type; first (18) and second (20) regions of opposite conductivity type formed in a surface of said body region and spaced from each other, said first and second regions forming a source and a drain of said transistor; a channel region (24) of said opposite conductivity type in said body region and interconnecting said first and second regions; and a surface region (26) of said one conductivity type overlying said channel region and extending from said first region to said second region, charcterised by a surface contact (32) on said surface region between said first and second regions, said surface contact having a conductivity greater than the conductivity of said surface layer, said body region beneath said channel region and said surface contact constituting electrically separate gates for said transistor.
Claim 2
Dependent Claim
143 words
A field effect transistor comprising a semiconductor body region (10,12) of one conductivity type; first (18) and second (20) regions of opposite conductivity type formed in a surface of said body region and spaced from each other, said first and second regions forming a source and a drain of said transistor; a channel region (24) of said opposite conductivity type in said body region and interconnecting said first and second regions; and a surface region (26) of said one conductivity type overlying said channel region and extending from said first region to said second region, charcterised by a surface contact (32) on said surface region between said first and second regions, said surface contact having a conductivity greater than the conductivity of said surface layer, said body region beneath said channel region and said surface contact constituting electrically separate gates for said transistor.
Claim 3
Dependent Claim
22 words
A field effect transistor as defined by claim 1 wherein said surface contact (32) comprises polycrystalline silicon of said one conductivity type.
Claim 4
Dependent Claim
23 words
The field effect transistor as defined by claim 2 and further including a metal layer (34) on the surface of said polycrystalline silicone.
Claim 5
Dependent Claim
36 words
A field effect transistor as defined by claim 1 wherein said surface contact (32) comprises a diffusion barrier metal in contact with said surface region and a metal formed on the surface of said barrier metal.
Claim 6
Dependent Claim
51 words
A field effect transistor as defined by any foregoing claim and further including a third doped region (30) of said one conductivity type in said surface region beneath said surface contact, said third doped region having a dopant concentration greater than the dopant concentration of the remainder of said surface region.
Claim 7
Dependent Claim
38 words
A field effect transistor as defined by any foregoing claim wherein said semiconductor body region comprises an epitaxial layer (10), and further including a substrate (12) of said opposite conductivity type on which said epitaxial layer is formed.
Claim 8
Dependent Claim
40 words
A field effect transistor as defined by claim 6 and further including a buried layer (16) of said first conductivity type formed in said substrate at the interface of said epitaxial layer and positioned beneath said first and second regions.
Claim 9
Dependent Claim
36 words
A field effect transistor as defined by claim 6 or 7 and further including an isolation region (14) extending from the surface of said epitaxial layer to said substrate and surrounding said first and second regions.
Claim 10
Dependent Claim
18 words
A field effect transistor as defined by claim 8 wherein said isolation region (14) comprises doped semiconductor material.
Claim 11
Dependent Claim
17 words
The field effect transistor as defined by claim 8 wherein said isolation region (14) comprises semiconductor oxide.
Claim 12
Dependent Claim
38 words
A field effect transistor as defined by any of claims 6 to 10 and further including a fourth region (22) of said first conductivity type formed in the surface of said epitaxial layer for contacting said epitaxial layer.
Claim 13
Dependent Claim
26 words
A field effect transistor as defined by claim 11 and further including metal contacts (28) to said first region, said second region, and said fourth region.