Patent US4438445A successfully refreshed from Google Patents.
US4438445A
Expired / Lapsed
US
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Variable capacitance diode and method of making the same
Assignee: Telefunken Electronic GmbH
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Filing: 1981-07-08
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Granted: 1984-03-20
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Expires: 2001-07-08
Abstract
Abstract A variable capacitance diode comprises a low resistance semi-conductor substrate on which is epitaxially deposited three layers, a first layer adjacent the substrate having an impurity concentration which decreases towards the substrate, a very thin intermediate region and a relatively thin surface region of lower doping than the intermediate region, a barrier being formed on or in the outer surface of the relativey thin surface region. The invention also includes a method of making such a diode.
Inventors
- 👤 Alexander Colquhoun
- 👤 Erhard Kohn
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 04:20
CPC Classifications
H; H10; H10D; H10D1/00; H10D1/60; H10D1/62; H10D1/64
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
96 words
A variable capacitance diode comprising a low resistance semiconductor substrate, and epitaxial layer arranged on said semiconductor substrate, and a barrier layer arranged in or on the major surface of said epitaxial layer opposite the major surface adjoining said semiconductor substrate; and wherein said epitaxial layer includes a relatively thin surface region which extends directly beneath the barrier layer and which is less heavily doped than an adjoining very thin intermediate region, and a further region which extends from said intermediate region to said substrate and has an impurity concentration which decreases towards said semiconductor substrate.
Claim 2
Dependent Claim
96 words
A variable capacitance diode comprising a low resistance semiconductor substrate, and epitaxial layer arranged on said semiconductor substrate, and a barrier layer arranged in or on the major surface of said epitaxial layer opposite the major surface adjoining said semiconductor substrate; and wherein said epitaxial layer includes a relatively thin surface region which extends directly beneath the barrier layer and which is less heavily doped than an adjoining very thin intermediate region, and a further region which extends from said intermediate region to said substrate and has an impurity concentration which decreases towards said semiconductor substrate.
Claim 3
Dependent Claim
23 words
A variable capacitance diode as defined in claim 1, wherein the impurity concentration in said further region decreases continuously towards said semiconductor substrate.
Claim 4
Dependent Claim
41 words
A variable capacitance diode as defined in claim 1, wherein the impurity concentration in said further region decreases continuously to a certain value and then remains constant in the remaining portion of said further region which extends to said semiconductor substrate.
Claim 5
Dependent Claim
18 words
A variable capacitance diode as defined in claim 1, wherein said barrier layer comprises a rectifying metal/semiconductor junction.
Claim 6
Dependent Claim
22 words
A variable capacitance diode as defined in claim 1, wherein said relatively thin surface region is approximately 0.5 to 1 μm thick.
Claim 7
Dependent Claim
20 words
A variable capacitance diode as defined in claim 1, wherein said intermediate region is approximately 0.05 to 0.2 μm thick.
Claim 8
Dependent Claim
24 words
A variable capacitance diode as defined in claim 1, wherein the semiconductor body comprising said substrate, and said epitaxial layer comprises n-conducting Ga As.
Claim 9
Dependent Claim
42 words
A variable capacitance diode as defined in claim 1, wherein the said relatively thin surface region has an impurity concentration of less than 10 16 atoms/cm 3 and said intermediate region has an impurity concentration of approximately 2-5×10 16 atoms/cm 3 .
Claim 10
Dependent Claim
29 words
A variable capacitance diode as defined in claim 2, wherein said further region has an impurity concentration of approximately 10 15 -5·10 15 atoms/cm 3 at said semiconductor substrate.
Claim 11
Dependent Claim
29 words
A variable capacitance diode as defined in claim 1 wherein said intermediate region has an impurity concentration which is greater than the maximum impurity concentration of said further region.
Claim 12
Dependent Claim
40 words
A variable capacitance diode as defined in claim 1 wherein said further region has an impurity concentration which decreases from approximately 10 16 atoms/cm 3 adjacent said intermediate region to approximately 10 15 -5·10 15 atoms/cm 3 adjacent said substrate.
Claim 13
Dependent Claim
119 words
A variable capacitance diode comprising: a low resistance semiconductor substrate; a first semiconductor epitaxial layer of one conductivity type disposed on said substrate and having an impurity concentration which decreases toward said substrate; a very thin second semiconductor epitaxial layer of said one conductivity type disposed on said first epitaxial layer and having a constant impurity concentration which is greater than that of said first epitaxial layer; a third relatively thin semiconductor epitaxial layer of said one conductivity type disposed on said second layer and having an impurity concentration which is less than that of said second layer; and means disposed in or on the surface of said third layer for forming a barrier layer with said third layer.
Claim 14
Dependent Claim
119 words
A variable capacitance diode comprising: a low resistance semiconductor substrate; a first semiconductor epitaxial layer of one conductivity type disposed on said substrate and having an impurity concentration which decreases toward said substrate; a very thin second semiconductor epitaxial layer of said one conductivity type disposed on said first epitaxial layer and having a constant impurity concentration which is greater than that of said first epitaxial layer; a third relatively thin semiconductor epitaxial layer of said one conductivity type disposed on said second layer and having an impurity concentration which is less than that of said second layer; and means disposed in or on the surface of said third layer for forming a barrier layer with said third layer.
Claim 15
Dependent Claim
62 words
A variable capacitance diode as defined in claim 12 wherein: said first layer has an impurity concentration which decreases from approximately 10 16 atoms/cm 3 to approximately 1-5·10 15 atoms/cm 3 ; said second layer has an impurity concentration of approximately 2-5×10 16 atoms/cm 3 ; and said third layer has an impurity concentration slightly less than 10 16 atoms/cm 3 .
Claim 16
Dependent Claim
31 words
A variable capacitance diode as defined in claim 13 wherein said second layer is approximately 0.05 to 0.2 μm thick and said third layer is approximately 0.5 to 1 μm thick.
Claim 17
Dependent Claim
22 words
A variable capacitance diode as defined in claim 14 wherein said impurity concentration in said first layer decreases continuously toward said substrate.
Claim 18
Dependent Claim
46 words
A variable capacitance diode as defined in claim 14 wherein said impurity concentration in said first layer decreases continuously towards said substrate in a certain portion of said first layer adjacent said second layer and then remains constant throughout the remaining portion of said first layer.
Claim 19
Dependent Claim
38 words
A variable capacitance diode as defined in claim 14 wherein said means forming said barrier layer comprises a metal layer disposed on said surface of said third layer and forming a rectifying metal/semiconductor junction with said third layer.
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