Measurement of collector-base junction avalanche multiplication effects in advanced UHV/CVD SiGe HBT´s

Author

Niu, Guofu ; Cressler, John D. ; Zhang, Shiming ; Gogineni, Usha ; Ahlgren, David C.

Author_Institution

Alabama Microelectron. Sci. & Technol. Center, Auburn Univ., AL, USA

Volume

46

Issue

5

fYear

1999

fDate

5/1/1999 12:00:00 AM

Firstpage

1007

Lastpage

1015

Abstract

This paper presents measurements of the avalanche multiplication factor (M-1) in SiGe HBTs using a new technique capable of separating the avalanche multiplication and Early effect contributions to the increase of collector current with collector-base bias, as well as allowing safe measurements at practical current densities. The impact of collector doping, current density, Ge profile, and operation temperature are reported for the first time using measured and simulated results from a production quality UHV/CVD SiGe HBT technology. Limitations of the technique in the presence of significant self-heating are discussed. By turning on the secondary hole impact ionization, we revealed the difference in impact ionization between strained SiGe and Si in the presence of the “dead space” effect. Despite its smaller bandgap, the compressively strained SiGe layer shows an apparent decrease in the secondary hole impact ionization rate compared to Si

Keywords

Ge-Si alloys; avalanche breakdown; current density; doping profiles; heterojunction bipolar transistors; impact ionisation; semiconductor device breakdown; semiconductor device measurement; semiconductor materials; Early effect contribution; Ge profile; SiGe; UHV/CVD SiGe HBT; avalanche multiplication effects; avalanche multiplication factor measurements; collector current; collector doping; collector-base bias; collector-base junction; compressively strained SiGe layer; current density; dead space effect; operation temperature; production quality HBT technology; secondary hole impact ionization; self-heating effect; Current density; Current measurement; Density measurement; Doping profiles; Germanium silicon alloys; Impact ionization; Production; Silicon germanium; Temperature; Time measurement;

fLanguage

English

Journal_Title

Electron Devices, IEEE Transactions on

Publisher

ieee

ISSN

0018-9383

Type

jour

DOI

10.1109/16.760410

Filename

760410