Double-polysilicon self-aligned sige

C lateral heterojunction bipolar transistors: design and simulation

P. Pengpad*, D. M. Bagnall

*Corresponding author for this work

Research output: Chapter in Book/Report/Conference proceedingConference proceeding contribution

Abstract

A new design of SiGe:C lateral heterojunction bipolar transistor is introduced. The design utilises a double-polysilicon self-aligned structure to maximise the highfrequency performance of the device. Silicon-on-oxide (SOI) wafers are used to isolate devices from the substrate and to minimise parasitic substrate capacitances (CJCS0) to around 1.3-2.6fF. A SOI thickness of 0.1um combined with 0.13-0.25um lithographic resolutions provides transistors with dimensions of (0.1x0.39)um2 and (0.1x0.75)um2, respectively. These devices should provide an estimated emitter/base junction capacitance (CJE0) in the range 0.8-1.5fF, while simple device isolation is predicted to produce a small collector/base junction capacitance (CJC0) of 1.3-2.5fF. Furthermore, use of a double base contact helps to reduce the base resistance (RB) to 16-18u and a wide collector window directly contacted to the collector is estimated to result in around 16u collector resistance (RC). By taking all parameters into account a cut-off frequency (fT) of 195-395GHz and maximum oscillation frequency (fmax) of 473-983GHz are predicted for this design, in addition a gain of around 340 and1.59-2.84ps ECL propagation delay time, at a current of 4-8mA can be achieved. Our simulations indicate that this new double-polysilicon self-aligned structure could outperform all other SiGe heterojunction bipolar transistors that have been reported.

Original languageEnglish
Title of host publicationProceedings of the 10th Anniversary International Conference of the European Society for Precision Engineering and Nanotechnology, EUSPEN 2008
Publishereuspen
Pages493-497
Number of pages5
Volume2
ISBN (Electronic)9780955308253
Publication statusPublished - 2008
Externally publishedYes
Event10th Anniversary International Conference of the European Society for Precision Engineering and Nanotechnology, EUSPEN 2008 - Zurich, Switzerland
Duration: 18 May 200822 May 2008

Conference

Conference10th Anniversary International Conference of the European Society for Precision Engineering and Nanotechnology, EUSPEN 2008
CountrySwitzerland
CityZurich
Period18/05/0822/05/08

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