SiGe base bipolar technology with 74 GHz f/sub max/ and 11 ps gate delay

Meister, T.F.; Schäfer, H.; Franosch, M.; Molzer, W.; Aufinger, Klaus; Scheler, Ulrich; Walz, C.; Stolz, H.; Boguth, S.; Böck, J.

doi:10.1109/iedm.1995.499324

Cited by 45 publications

(19 citation statements)

References 5 publications

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“…A factor (SiGe) can be defined to take the SiGe alloy into account, which is expressed as for and for (5) This factor is assumed not to vary strongly with temperature and will be considered as a constant in the following analysis.…”

Section: The Analysis Methodsmentioning

confidence: 99%

“…Thanks to the heterojunction effect, thin, heavily doped base can be used to reduce the transit time in the base without compromising the base resistance or the emitter injection efficiency [1], [2]. Over the last ten years, SiGe technology and heterojunction bipolar transistor (HBT) design has progressed considerably, and has reached the point of record cut-off frequencies above 100 GHz [3], [4] and record ECL gate delays down to 11 ps [5], [6].…”

Section: Introductionmentioning

confidence: 99%

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Determination of bandgap narrowing and parasitic energy barriers in SiGe HBT's integrated in a bipolar technology

Tron

Hashim

Ashburn

et al. 1997

IEEE Trans. Electron Devices

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Abstract-This paper describes a method for characterizing the bandgap narrowing and parasitic energy barrier in SiGe heterojunction bipolar transistors (HBT's), fabricated using a singlepolysilicon self-aligned bipolar process. From a comprehensive study of the temperature dependence of the collector current, the bandgap narrowing in the base due to germanium has been dissociated from that due to the heavy dopant concentration. The same approach has been used to characterize the height and width of parasitic energy barriers which appear when boron out-diffusion from the SiGe base is present. The method has been applied to SiGe heterojunction bipolar transistors fabricated using a single polysilicon, self aligned, bipolar process, as well as mesa transistors. The experimental results show that small geometry transistors have degraded collector currents due to boron out-diffusion around the perimeter of the emitter. This behavior has been explained by accelerated boron diffusion due to point defect generated during the extrinsic base implant. The values of undoped SiGe spacer thickness needed to suppress the parasitic energy barrier are described. Finally, high-frequency results are reported, which correlate the frequency transition to these parasitic energy barriers.

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Section: The Analysis Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Determination of bandgap narrowing and parasitic energy barriers in SiGe HBT's integrated in a bipolar technology

Tron

Hashim

Ashburn

et al. 1997

IEEE Trans. Electron Devices

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“…This approach has the advantage of being compatible with conventional double polysilicon bipolar technology, which minimizes parasitic collector/base capacitance and gives very fast digital circuit performance. ECL gate delays of 11 ps [5] and 9.3 ps [6] have been reported for this approach.…”

mentioning

confidence: 99%

“…delays around 10 ps [5], [6] and high frequency analog circuits for wireless communication systems [7]. However, in spite of this impressive progress, no single process architecture has yet emerged as the dominant approach for manufacturing SiGe HBT integrated circuits.…”

mentioning

confidence: 99%

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Leakage current mechanisms in SiGe HBTs fabricated using selective and nonselective epitaxy

Schiz

Lamb

Cristiano

et al. 2001

IEEE Trans. Electron Devices

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Abstract-SiGe heterojunction bipolar transistors (HBTs) have been fabricated using selective epitaxy for the Si collector, followed in the same growth step by nonselective epitaxy for the p + SiGe base and n-Si emitter cap. DC electrical characteristics are compared with cross-section TEM images to identify the mechanisms and origins of leakage currents associated with the epitaxy in two different types of transistor. In the first type, the polysilicon emitter is smaller than the collector active area, so that the extrinsic base implant penetrates into the single-crystal Si and SiGe around the perimeter of the emitter and the polycrystalline Si and SiGe extrinsic base. In these transistors, the Gummel plots are near-ideal and there is no evidence of emitter/collector leakage. In the second type, the collector active area is smaller than the polysilicon emitter, so the extrinsic base implant only penetrates into the polysilicon extrinsic base. In these transistors, the leakage currents observed depend on the base doping level. In transistors with a low doped base, emitter/collector and emitter/base leakage is observed, whereas in transistors with a high doped base only emitter/base leakage is observed. The emitter/collector leakage is explained by punch through of the base caused by thinning of the SiGe base at the emitter perimeter. The emitter/base leakage is shown to be due to a Poole-Frenkel mechanism and is explained by penetration of the emitter/base depletion region into the p+ polysilicon extrinsic base at the emitter periphery. Variable collector/base reverse leakage currents are observed and a variety of mechanisms are observed, including Shockley-Read-Hall recombination, trap assisted tunneling, Poole-Frenkel and band to band tunneling. These results are explained by the presence of polysilicon grains on the sidewalls of the field oxide at the collector perimeter.

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SiGe/Si Heterojunction Bipolar Transistors and Circuits

Rieh

2011

Comprehensive Semiconductor Science and Technology

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SiGe base bipolar technology with 74 GHz f/sub max/ and 11 ps gate delay

Cited by 45 publications

References 5 publications

Determination of bandgap narrowing and parasitic energy barriers in SiGe HBT's integrated in a bipolar technology

Determination of bandgap narrowing and parasitic energy barriers in SiGe HBT's integrated in a bipolar technology

Leakage current mechanisms in SiGe HBTs fabricated using selective and nonselective epitaxy

SiGe/Si Heterojunction Bipolar Transistors and Circuits

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