Improved high-frequency equivalent circuit model based on distributed effects for SiGe HBTs with CBE layout

In this paper, we present an improved high-frequency equivalent circuit for SiGe heterojunction bipolar transistors（HBTs） with a CBE layout, where we consider the distributed effects along the base region. The actual device structure is divided into three parts： a link base region under a spacer oxi...

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Bibliographic Details
Published inChinese physics B Vol. 26; no. 9; pp. 502 - 508
Main Author 孙亚宾 李小进 张金中 石艳玲
Format Journal Article
LanguageEnglish
Published 01.08.2017
Subjects
CBE
SiGe异质结双极晶体管
传输线方程
小信号等效电路
布局改进
等效电路模型
集电极电阻
高频
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Summary:In this paper, we present an improved high-frequency equivalent circuit for SiGe heterojunction bipolar transistors（HBTs） with a CBE layout, where we consider the distributed effects along the base region. The actual device structure is divided into three parts： a link base region under a spacer oxide, an intrinsic transistor region under the emitter window,and an extrinsic base region. Each region is considered as a two-port network, and is composed of a distributed resistance and capacitance. We solve the admittance parameters by solving the transmission-line equation. Then, we obtain the smallsignal equivalent circuit depending on the reasonable approximations. Unlike previous compact models, in our proposed model, we introduce an additional internal base node, and the intrinsic base resistance is shifted into this internal base node,which can theoretically explain the anomalous change in the intrinsic bias-dependent collector resistance in the conventional compact model.
Bibliography:In this paper, we present an improved high-frequency equivalent circuit for SiGe heterojunction bipolar transistors（HBTs） with a CBE layout, where we consider the distributed effects along the base region. The actual device structure is divided into three parts： a link base region under a spacer oxide, an intrinsic transistor region under the emitter window,and an extrinsic base region. Each region is considered as a two-port network, and is composed of a distributed resistance and capacitance. We solve the admittance parameters by solving the transmission-line equation. Then, we obtain the smallsignal equivalent circuit depending on the reasonable approximations. Unlike previous compact models, in our proposed model, we introduce an additional internal base node, and the intrinsic base resistance is shifted into this internal base node,which can theoretically explain the anomalous change in the intrinsic bias-dependent collector resistance in the conventional compact model.
11-5639/O4
SiGe heterojunction bipolar transistors（HBT） small-signal equivalent circuit distributed effects CBE layout
ISSN:1674-1056
2058-3834
DOI:10.1088/1674-1056/26/9/098502