Share Email Print

Proceedings Paper

Low-frequency noise and random telegraph signal noise in SiGe:C heterojunction bipolar transistors: impact of carbon concentration
Author(s): Jeremy Raoult; Colette Delseny; Fabien Pascal; Mathieu Marin; M. Jamal Deen
Format Member Price Non-Member Price
PDF $14.40 $18.00
cover GOOD NEWS! Your organization subscribes to the SPIE Digital Library. You may be able to download this paper for free. Check Access

Paper Abstract

We have investigated the influence of carbon concentration on the low frequency noise (LFN) of Si/SiGe:C Heterojunction Bipolar Transistors (HBTs). The HBTs are supplied by ST-Microelectronics Crolles and are based on a 0.13 &mgr;m BiCMOS technology. Three types of transistors were studied; they only differ by the amount of carbon incorporated. When carbon is incorporated, representative noise spectra of the input current spectral density, SiB, show important generation-recombination (G-R) components, while no such components are observed in carbon free transistors. When the 1/f noise component is unambiguously observed, the associated figure of merit KB has a very good value close to 4.10-10 &mgr;m2. In this paper we focus on the analysis of the G-R components associated with the presence of the carbon. Most of the observed Lorentzians are associated with Random Telegraph Signal (RTS) noise. No RTS noise is found in carbon free devices. The RTS noise appears to be due to electrically active defects formed by the addition of carbon, typically observed for concentrations above the bulk solid solubility limit in silicon. The RTS noise, amplitude &Dgr;IB and the mean pulse widths (tH, tL), are analyzed as a function of bias voltage and temperature. The RTS amplitude is found to scale with the base current and to decrease exponentially with temperature, independently of the carbon concentration. The mean pulse widths are found to decrease rapidly with bias voltage, as 1/exp(qVBE/kT) or stronger. Our results confirm that electrically active C-related defects are localized in the base-emitter junction, and the RTS amplitude is explained by a model based on voltage barrier height fluctuations across the base-emitter junction induced by trapped carriers in the space charge region. The observed bias dependence of mean pulse widths seems to indicate that two capture processes are involved, electron and hole capture. These C-related defects behave like recombination centers with deep energy levels rather than electron or hole traps involving trapping-detrapping process.

Paper Details

Date Published: 22 June 2007
PDF: 11 pages
Proc. SPIE 6600, Noise and Fluctuations in Circuits, Devices, and Materials, 66000G (22 June 2007); doi: 10.1117/12.724559
Show Author Affiliations
Jeremy Raoult, IES, CNRS-Univ. Montpellier (France)
Colette Delseny, IES, CNRS-Univ. Montpellier (France)
Fabien Pascal, IES, CNRS-Univ. Montpellier (France)
Mathieu Marin, STMicroelectronics (France)
M. Jamal Deen, McMaster Univ. (Canada)

Published in SPIE Proceedings Vol. 6600:
Noise and Fluctuations in Circuits, Devices, and Materials
Massimo Macucci; Lode K.J. Vandamme; Carmine Ciofi; Michael B. Weissman, Editor(s)

© SPIE. Terms of Use
Back to Top