EP0300803A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
High-frequency bipolar transistor and its fabrication method
Assignee: Panasonic Holdings Corp
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Filing: 1988-07-22
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Granted: —
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Expires: 2008-07-22
Abstract
Abstract A bipolar transistor with improved high-frequency performance is invented. The improvement is attained by eliminating a parasitic base-collector capacitance. The invented transistor is constructed upon a semi-insulating substrate, and wherein a region which underlies an extrinsic base region is semi-insulative such that the extrinsic base region does not substantially overlap the collector contact region and the collector region when viewed in the direction perpendicular to the substrate. Here, it's worthwhile to point out that a portion under the extrinsic base region is made completely semi-insulative down to the substrate. As a result, the transistor has substantially no parasitic base-collector capacitance. Also, a novel method, utilizing a self-align technique which uses a "first mask" for defining a collector contact region and a collector region, a "second mask" for defining an extrinsic base region, and a "third mask" determined by self-alignment using the first and the second mask for defining an emitter region, is disclosed to fabricate the bipolar transistor mentioned above.
Inventors
- 👤 Yorito Ota
- 👤 Masanori Inada
- 👤 Manabu Yanagihara
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-28 01:49
CPC Classifications
H; H10; H10D; H10D10/00; H10D10/01; H10D10/021; H10D10/80; H10D10/821; H10D62/00; H10D62/10; H10D62/17; H10D62/177; H10D62/80; H10D62/85; Y; Y10; Y10S; Y10S148/00; Y10S148/01; Y10S148/072
Claims Analysis
Total Claims: 24
Claim 1
Independent Claim
119 words
A bipolar transistor, which is constructed upon a semi-insulating substrate and comprises: a collector contact region formed on said substrate; a collector region formed on the collector contact region; a semi-insulative region formed on the substrate so as to extend from both the collector contact region and the collector region; a base region having a intrinsic base region formed on the collector region and an extrinsic base region formed on the semi-insulative region so as to extend from the intrinsic base region whereby the extrinsic base region is avoided to substantially overlap the collector region and the collector contact region when viewed in the direction perpendicular to the substrate; and an emitter region formed on the intrinsic base region.
Claim 2
Dependent Claim
119 words
A bipolar transistor, which is constructed upon a semi-insulating substrate and comprises: a collector contact region formed on said substrate; a collector region formed on the collector contact region; a semi-insulative region formed on the substrate so as to extend from both the collector contact region and the collector region; a base region having a intrinsic base region formed on the collector region and an extrinsic base region formed on the semi-insulative region so as to extend from the intrinsic base region whereby the extrinsic base region is avoided to substantially overlap the collector region and the collector contact region when viewed in the direction perpendicular to the substrate; and an emitter region formed on the intrinsic base region.
Claim 3
Dependent Claim
27 words
The bipolar transistor of claim 1 wherein the bandgap of a material of the emitter region is wider than that of a material of the base region.
Claim 4
Dependent Claim
27 words
The bipolar transistor of claim 2, wherein the collector region is made of GaAs, and the semi-insulative region is made by oxygen-ion implantation into a GaAs layer.
Claim 5
Dependent Claim
32 words
The bipolar transistor of claim 1, further comprising a base electrode which is formed on the extrinsic base region and divided into two portions arranged at both sides of the emitter region.
Claim 6
Dependent Claim
32 words
The bipolar transistor of claim 1, further comprising a collector electrode which is formed on the collector contact region and divided into two portions arranged at both sides of the emitter region.
Claim 7
Dependent Claim
15 words
The bipolar transistor of claim 1, wherein the semi-insulative region is made by ion implantation.
Claim 8
Dependent Claim
24 words
The bipolar transistor of claim 6, wherein ions are implanted into the extrinsic base region to reduce the resistance of the extrinsic base region.
Claim 9
Dependent Claim
119 words
A bipolar transistor, which is constructed upon a semi-insulating substrate and comprises: an emitter contact region formed on said substrate; an emitter region formed on the emitter contact region; a semi-insulative region formed on the substrate so as to extend from both the emitter contact region and the emitter region; a base region having an intrinsic base region formed on the emitter region and an extrinsic base region formed on the semi-insulative region so as to extend from the intrinsic base region whereby the extrinsic base region is avoided to substantially overlap the emitter region and the emitter contact region when viewed in the direction perpendicular to the substrate; and a collector region formed on the intrinsic base region.
Claim 10
Dependent Claim
119 words
A bipolar transistor, which is constructed upon a semi-insulating substrate and comprises: an emitter contact region formed on said substrate; an emitter region formed on the emitter contact region; a semi-insulative region formed on the substrate so as to extend from both the emitter contact region and the emitter region; a base region having an intrinsic base region formed on the emitter region and an extrinsic base region formed on the semi-insulative region so as to extend from the intrinsic base region whereby the extrinsic base region is avoided to substantially overlap the emitter region and the emitter contact region when viewed in the direction perpendicular to the substrate; and a collector region formed on the intrinsic base region.
Claim 11
Dependent Claim
27 words
The bipolar transistor of claim 8 wherein the bandgap of a material of the emitter region is wider than that of a material of the base region.
Claim 12
Dependent Claim
27 words
The bipolar transistor of claim 9, wherein the emitter region is made of AlGaAs, and the semi-insulative region is made by oxygen-ion implantation into a AlGaAs layer.
Claim 13
Dependent Claim
32 words
The bipolar transistor of claim 8, further comprising a base electrode which is formed on the extrinsic base region and divided into two portions arranged at both sides of the collector region.
Claim 14
Dependent Claim
32 words
The bipolar transistor of claim 8, further comprising an emitter electrode which is formed on the emitter contact region and divided into two portions arranged at both sides of the collector region.
Claim 15
Dependent Claim
15 words
The bipolar transistor of claim 8, wherein the semi-insulative region is made by ion implantation.
Claim 16
Dependent Claim
24 words
The bipolar transistor of claim 13, wherein ions are implanted into the extrinsic base region to reduce the resistance of the extrinsic base region.
Claim 17
Independent Claim
261 words
A method of fabricating a bipolar transistor comprising the steps of: 1) forming a multilayer structure by sequentially stacking on a semi-insulating substrate, a collector contact layer, a collector layer, a base layer, and an emitter layer in this order; 2) forming a first mask on a part of the multilayer structure; 3) changing the collector contact layer and the collector layer to be a first semi-insulative region by a deep ion-implantation at portions except for portions below the first mask so that the portions of the collector contact layer and the collector layer below the first mask become a collector contact region and a collector region, respectively; 4) forming a second mask on a part of the multilayer structure to partly overlap a part of the first mask; 5) removing the first mask except for the part overlapped with the second mask; 6) changing the base layer to be a second semi-insulative region by a shallow ion-implantation at a portion except for a portion below the second mask so that the portion of the base layer below the second mask becomes a base region having an extrinsic base region formed on the first semi-insulative region; 7) removing the second mask so that the part of the first mask which was overlapped with the secon dmask remains as a third mask; 8) etching off the emitter layer at a portion except for a portion below the third mask so that the portion of the emitter layer below the third mask remains as an emitter region; and 9) removing the third mask.
Claim 18
Independent Claim
261 words
A method of fabricating a bipolar transistor comprising the steps of: 1) forming a multilayer structure by sequentially stacking on a semi-insulating substrate, a collector contact layer, a collector layer, a base layer, and an emitter layer in this order; 2) forming a first mask on a part of the multilayer structure; 3) changing the collector contact layer and the collector layer to be a first semi-insulative region by a deep ion-implantation at portions except for portions below the first mask so that the portions of the collector contact layer and the collector layer below the first mask become a collector contact region and a collector region, respectively; 4) forming a second mask on a part of the multilayer structure to partly overlap a part of the first mask; 5) removing the first mask except for the part overlapped with the second mask; 6) changing the base layer to be a second semi-insulative region by a shallow ion-implantation at a portion except for a portion below the second mask so that the portion of the base layer below the second mask becomes a base region having an extrinsic base region formed on the first semi-insulative region; 7) removing the second mask so that the part of the first mask which was overlapped with the secon dmask remains as a third mask; 8) etching off the emitter layer at a portion except for a portion below the third mask so that the portion of the emitter layer below the third mask remains as an emitter region; and 9) removing the third mask.
Claim 19
Dependent Claim
31 words
The method of claim 15, wherein the bandgap of a material of the emitter layer described in the step 1) is wider than that of a material of the base layer.
Claim 20
Dependent Claim
42 words
The method of claim 15, further comprising between the step 3) and the step 4), an additional step of implanting ions into the extrinsic base region upon the first semi-insulative region such that the resistance of said extrinsic base region is reduced.
Claim 21
Independent Claim
261 words
A method of fabricating a bipolar transistor comprising the steps of: 1) forming a multilayer structure by sequentially stacking on a semi-insulating substrate, an emitter contact layer, an emitter layer, a base layer, and a collector layer in this order; 2) forming a first mask on a part of the multilayer structure; 3) changing the emitter contact layer and the emitter layer to be a first semi-insulative region by a deep ion-implantation at portions except for portions below the first mask so that the portions of the emitter contact layer and the emitter layer below the first mask become an emitter contact region and an emitter region, respectively; 4) forming a second mask on a part of the multilayer structure to partly overlap a part of the first mask; 5) removing the first mask except for the part overlapped with the second mask; 6) changing the base layer to be a second semi-insulative region by a shallow ion-implantation at a portion except for a portion below the second mask so that the portion of the base layer below the second mask becomes a base region having an extrinsic base region formed on the first semi-insulative region; 7) removing the second mask so that the part of the first mask which was overlapped with the second mask remains as a third mask; 8) etching off the collector layer at a portion except for a portion below the third mask so that the portion of the collector layer below the third mask remains as a collector region; and 9) removing the third mask.
Claim 22
Independent Claim
261 words
A method of fabricating a bipolar transistor comprising the steps of: 1) forming a multilayer structure by sequentially stacking on a semi-insulating substrate, an emitter contact layer, an emitter layer, a base layer, and a collector layer in this order; 2) forming a first mask on a part of the multilayer structure; 3) changing the emitter contact layer and the emitter layer to be a first semi-insulative region by a deep ion-implantation at portions except for portions below the first mask so that the portions of the emitter contact layer and the emitter layer below the first mask become an emitter contact region and an emitter region, respectively; 4) forming a second mask on a part of the multilayer structure to partly overlap a part of the first mask; 5) removing the first mask except for the part overlapped with the second mask; 6) changing the base layer to be a second semi-insulative region by a shallow ion-implantation at a portion except for a portion below the second mask so that the portion of the base layer below the second mask becomes a base region having an extrinsic base region formed on the first semi-insulative region; 7) removing the second mask so that the part of the first mask which was overlapped with the second mask remains as a third mask; 8) etching off the collector layer at a portion except for a portion below the third mask so that the portion of the collector layer below the third mask remains as a collector region; and 9) removing the third mask.
Claim 23
Dependent Claim
31 words
The method of claim 18, wherein the bandgap of a material of the emitting layer described in the step 1) is wider than that of a material of the base layer.
Claim 24
Dependent Claim
42 words
The method of claim 18, further comprising, between the step 3) and the step 4), an additional step of implanting ions into the extrinsic base region upon the first semi-insulative region such that the resistance of said extrinsic base region is reduced.
References Cited (Backward Citations)
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