Semiconductor device and a method of making the same

Claim 2

A field effect transistor comprising a semiconductor substrate of monocrystalline material of one conductivity type, having one or more epitaxial layers thereon all of a conductivity type opposite to that of said substrate, the uppermost of said epitaxial layers including a gate region therein of the same conductivity type as said substrate extending at least partially therethrough, said uppermost layer also including low resistivity polycrystalline regions of the same conductivity type as said first epitaxial layer on opposite sides of said gate region extending from the outer surface of the uppermost layer to a point in close proximity to the layer lying immediately therebelow, said polycrystalline regions being of substantially constant low resistivity throughout and serving as drain and source electrodes.

Claim 3

A field effect transistor comprising a substrate of one conductivity type and at least two epitaxial layers of the opposite conductivity type thereon of monocrystalline semiconductor material, the upper of said epitaxial layers having at least three low resistivity polycrystalline regions therein spaced substantially in a line, the middle one of said polycrystalline regions being of the same conductivity type as said substrate and the other two polycrystalline regions being of opposite conductivity type as that of said substrate, each of said polycrystalline regions extending from the outer surface of the upper of said layers to an area substantially in proximity to the upper surface of the lower of said layers, the upper outer ends of said polycrystalline regions being provided respectively with drain, gate and source electrodes on the exposed surface of said upper epitaxial layer, and the lower of said epitaxial layers providing a channel between said source and drain electrodes, said polycrystalline regions being of substantially constant low resistivity throughout.

Claim 4

A field effect transistor comprising a substrate of one conductivity type and at least two epitaxial layers of the opposite conductivity type thereon of monocrystalline semiconductor material, the upper of said epitaxial layers having at least three low resistivity polycrystalline regions therein spaced substantially in a line, the middle one of said polycrystalline regions being of the same conductivity type as said substrate and the other two polycrystalline regions being of opposite conductivity type as that of said substrate, each of said polycrystalline regions extending from the outer surface of the upper of said layers to an area substantially in proximity to the upper surface of the lower of said layers, the upper outer ends of said polycrystalline regions being provided respectively with drain, gate and source electrodes on the exposed surface of said upper epitaxial layer, and the lower of said epitaxial layers providing a channel between said source and drain electrodes, said polycrystalline regions being of substantially constant low resistivity throughout.

Claim 5

A field effect transistor comprising a monocrystalline substrate of one conductivity type, an epitaxial monocrystalline layer thereon of the opposite conductivity type, said epitaxial layer having a gate region extending from the surface thereof to a point interior of said layer and spaced upwardly from said substrate, said gate region being of the same conductivity type as said substrate, said layer having two low resistivity polycrystalline regions on opposite sides of and spaced from said gate region to substantially the surface of said substrate, said two polycrystalline regions being of substantially constant low resistivity throUghout and serving as drain and source electrodes.

Claim 6

A field effect transistor comprising a monocrystalline substrate of one conductivity type, an epitaxial monocrystalline layer thereon of the opposite conductivity type, said epitaxial layer having a gate region extending from the surface thereof to a point interior of said layer and spaced upwardly from said substrate, said gate region being of the same conductivity type as said substrate, said layer having two low resistivity polycrystalline regions on opposite sides of and spaced from said gate region to substantially the surface of said substrate, said two polycrystalline regions being of substantially constant low resistivity throUghout and serving as drain and source electrodes.

Claim 7

A remote cut-off field effect transistor comprising a monocrystalline substrate of one conductivity type, an epitaxial monocrystalline layer of the opposite conductivity type thereon and forming a junction with said substrate, a second epitaxial monocrystalline layer on said first layer having islands portions of polycrystalline semiconductor material thereon, said second layer forming a junction with said first layer, said polycrystalline portion of said second layer extending from the upper surface thereof to substantially the junction between said first and second layers and forming below its lower end or first channel, said polycrystalline portion of said second layer being doped with the same impurity type as said substrate, an isolated portion of said monocrystalline portion being doped with an impurity type the same as that of said substrate from the upper surface of said second layer to a region part way down to said first layer and forming below its lower end a second channel, said last mentioned polycrystalline portion and said isolated portion constituting gate electrode means, the portion of said second layer lying between said polycrystalline portion and said isolated portion constituting drain electrode means, and the portion of said second layer lying peripherally outside said polycrystalline portion and said isolated portion constituting source electrode means.

Claim 8

A remote cut-off field effect transistor comprising a monocrystalline substrate of one conductivity type, an epitaxial monocrystalline layer of the opposite conductivity type thereon and forming a junction with said substrate, a second epitaxial monocrystalline layer on said first layer having islands portions of polycrystalline semiconductor material thereon, said second layer forming a junction with said first layer, said polycrystalline portion of said second layer extending from the upper surface thereof to substantially the junction between said first and second layers and forming below its lower end or first channel, said polycrystalline portion of said second layer being doped with the same impurity type as said substrate, an isolated portion of said monocrystalline portion being doped with an impurity type the same as that of said substrate from the upper surface of said second layer to a region part way down to said first layer and forming below its lower end a second channel, said last mentioned polycrystalline portion and said isolated portion constituting gate electrode means, the portion of said second layer lying between said polycrystalline portion and said isolated portion constituting drain electrode means, and the portion of said second layer lying peripherally outside said polycrystalline portion and said isolated portion constituting source electrode means.