US 7,923,754 B2Granted

Bipolar transistor

AssigneeJapan Science and Technology Agency

InventorsYasuyuki Miyamoto, Tohru Yamamoto, Masashi Ishida

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Abstract

A bipolar transistor (1) comprising a subcollector layer (3), a collector layer (4, 5), a base layer (6) and an emitter layer (7) which are successively built up and having: the subcollector layer (3) formed with a projection (3A) and recesses (3B), an upper part above the projection constituting an intrinsic transistor region (1A) of the bipolar transistor; insulator layer (10) buried between the recesses of the subcollector layer and the collector layer (4); a boundary interface between the subcollector layer and the collector layer held between the insulator layers; the base layer (6) made of a single crystal layer and provided with a base electrode (12) on a region becoming an extrinsic base layer (6B) of the base layer; and the subcollector layer provided with a collector electrode (11). The bipolar transistor has advantages of its emitter made finer in width, a reduced parasitic capacitance between its base and collector and improved high-frequency characteristics.

Claims7

Dependent claims

A bipolar transistor having a subcollector layer, a collector layer, a base layer and an emitter layer, characterized in that:

said subcollector layer is formed with a projection and recesses;
said collector layer provided above an upper part of said projection of said subcollector is constituted as an intrinsic collector layer of the bipolar transistor;
said collector layer provided above an upper part of said recesses of said subcollector is constituted as an extrinsic collector layer of the bipolar transistor;
an insulator layer is buried between the recesses of said subcollector layer and said extrinsic collector layer;
a boundary interface between said projection of said subcollector layer and said intrinsic collector layer is sandwiched between said insulator layer;
said base layer is comprising of an intrinsic base layer and an extrinsic base layer, and is formed of a single crystal layer;
a base electrode is provided on said external base layer of said base layer;
and
said subcollector layer is provided with a collector electrode.

6 more elements

Dependencies are inferred from the claim text.

Facts

Application: 12/093,950Filed 16 Nov 2006
Priority: JP 2005-33499118 Nov 2005
Published: US 2009/0302351 A110 Dec 2009
Granted: 12 Apr 2011
Term ends: Not estimatedThe source records don’t support an estimate.

Classification5 codes

H10D 10/821
Heterojunction BJTs: vertical heterojunction BJTs
H10D 10/021
Manufacture or treatment: of heterojunction BJTs [HBT]
H10D 62/824
Heterojunctions: comprising only Group III-V materials heterojunctions, e.g. GaN/AlGaN heterojunctions
H10D 62/85
Characterised by the materials: being Group III-V materials, e.g. GaAs