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Bipolar transistor and method for fabricating the same

a technology of bipolar transistors and manufacturing methods, which is applied in the manufacture of semiconductor/solid-state devices, semiconductor devices, electrical apparatus, etc., can solve the problems of deterioration of the rf characteristic of hbt, thermal instability of high-power devices, and further temperature rise, so as to improve the rf characteristic without increasing the chip area, excellent thermal stability, and manufacturing cost

Inactive Publication Date: 2007-05-03
PANASONIC CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

The design enhances thermal stability and maintains excellent RF characteristics by reducing base resistance and chip area, while minimizing the need for special dielectric materials and additional process steps, thus lowering manufacturing costs.

Problems solved by technology

In such cases, the ON voltage between the emitter and the base decreases in some of the HBTs under high temperatures, so that the emitter current increases, thus causing further temperature rise.
As a result, operation of the high power device becomes thermally unstable.
Accordingly, current of an input signal input from the base electrodes 108 decreases to a larger extent, resulting in deterioration in the RF characteristic of the HBT.
This increases the chip area, thus increasing the cost for a chip.
In particular, if nitride silicon is used for a capacitive insulating film, a rectangular region with sides of 10 μm or more is required for every HBT in order to secure a capacitive value required as an input capacitance, resulting in that the cost for a chip remarkably increases.
In addition, it is also necessary to form ballast resistances and input capacitances after forming HBTs, so that the manufacturing cost increases.

Method used

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  • Bipolar transistor and method for fabricating the same
  • Bipolar transistor and method for fabricating the same
  • Bipolar transistor and method for fabricating the same

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Experimental program
Comparison scheme
Effect test

embodiment 1

Fabrication Method of Embodiment 1

[0085] Hereinafter, a method for fabricating the bipolar transistor of the first embodiment will be described with reference to the drawings.

[0086]FIGS. 2A through 2D and FIGS. 3A through 3C are cross-sectional views showing respective process steps of a method for fabricating the bipolar transistor of the first embodiment.

[0087] First, as shown in FIG. 2A, a collector contact layer 22 of GaAs doped with an n-type impurity, a collector-layer formation layer 23 of GaAs doped with a low-concentration n-type impurity, a base-layer formation layer (first semiconductor layer) 24 of GaAs doped with a high-concentration p-type impurity, an emitter-layer formation layer (second semiconductor layer) 25 of InGaP doped with an n-type impurity, and an emitter-contact-layer formation layer 26 of InGaAs which contains an n-type impurity and whose indium mole fraction gradually increases from 0 to 0.5 are formed by epitaxial growth over a substrate 21 of GaAs. T...

embodiment 2

[0098] Hereinafter, a bipolar transistor according to a second embodiment of the present invention will be described with reference to the drawings.

[0099]FIG. 4 shows a cross-sectional structure of a bipolar transistor of the second embodiment. In FIG. 4, each member in the bipolar transistor of the first embodiment is identified by the same reference numeral and the description thereof will be omitted herein.

[0100] As shown in FIG. 4, a collector contact layer 12, a collector layer 13 and a base layer 14 including an intrinsic base region 14a and an extrinsic base region 14b are provided in this order over a substrate 11. An emitter layer 41 including an emitter region 41a on the intrinsic base region 14a and a surface-protection region 41b on the extrinsic base region 14b. An emitter contact layer 16, an emitter electrode 17 and an upper emitter electrode 42 of a multilayer film as a stack of titanium, platinum and gold (Ti / Pt / Au) are formed in this order over the emitter region...

embodiment 3

Fabrication Method of Embodiment 3

[0122] Hereinafter, a method for fabricating the bipolar transistor of the third embodiment will be described with reference to the drawings.

[0123]FIGS. 7A through 7D are cross-sectional views showing respective process steps of a method for fabricating the bipolar transistor of the third embodiment. In FIGS. 7A through 7D, each member in the bipolar transistor of the first or second embodiment is identified by the same reference numeral and the description thereof will be omitted herein. A process step shown in FIG. 7A corresponds to the process step shown in FIG. 5A regarding the second embodiment.

[0124] First, as in the process steps shown in FIGS. 2A through 2C, a collector contact layer 22, a collector-layer formation layer 23, a base-layer formation layer 24, an emitter-layer formation layer 25, an emitter-contact-layer formation layer 26 and an emitter-electrode formation layer 27 are stacked in this order over a substrate 21. Thereafter, e...

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Abstract

A bipolar transistor includes: a first semiconductor layer having an intrinsic base region and an extrinsic base region; and a second semiconductor layer having a portion located on the intrinsic base region to be an emitter region or a collector region. A capacitive film is provided on the extrinsic base region using the same semiconductor material as that for the second semiconductor layer. A base electrode is formed on the first semiconductor layer to cover the capacitive film and the extrinsic base region.

Description

BACKGROUND OF THE INVENTION [0001] The present invention relates to bipolar transistors capable of being used as high power transistors using radio frequencies, and to methods for fabricating the same. [0002] Group III-V compound semiconductors of, for example, gallium arsenide (GaAs) or indium phosphorus (InP) have the following advantages. For example, the Group III-V compound semiconductors exhibit excellent electrical characteristics in, for example, electron mobility and electron saturation velocity, as compared to silicon (Si)-based semiconductor materials. In addition, the Group III-V compound semiconductors can be used in designing semiconductor devices with desired energy band structures utilizing a heterojunction or can be used as semi-insulating substrates. [0003] In particular, a heterojunction bipolar transistor (HBT) which uses, for its emitter layer, a Group III-V compound semiconductor having a wider band gap than the base layer exhibits characteristics such as being...

Claims

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Application Information

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Patent Type & Authority Applications(United States)
IPC IPC(8): H01L31/00H01L29/739H01L21/331H01L29/08H01L29/423H01L29/737
CPCH01L29/0817H01L29/42304H01L29/66318H01L29/7371H01L29/20
Inventor YANAGIHARA, MANABUTSURUMI, NAOHIROTANAKA, TSUYOSHIUEDA, DAISUKE
Owner PANASONIC CORP