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Proceedings Paper

Extended velocity overshoot in InGaAs collectors for high-speed heterojunction bipolar transistors
Author(s): Christine M. Maziar; Mark H. Somervell; Carl S. Kyono
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Paper Abstract

As 111-V device fabrication technology continues to improve and performance limiting parasitics are eliminated, the intrinsic speed of any given device structure and options for increasing that speed are of greater interest to device researchers and technologists. One approach to improving heterojunction bipolar transistor (HBT) high-frequency performance is to reduce the transit time across the collector space charge region by carefully tailoring the electric field in the collector in such a fashion as to extend or enhance velocity overshoot in the space charge region. This technique was first described' and demonstrated23 for AlGa,_As/GaAs HBTs. Recently, structures composed of materials lattice matched to InP substrates45 have emerged as champions in the race for high-speed and optical applications honors. Because these devices have utilized conventional collector structures, further gains can be achieved by application of collectors designed for enhanced or extended velocity overshoot. This is easily seen by noting that the extended velocity overshoot condition is more easily achieved in 1n053Ga047As than in GaAs, in large part due to the larger F - L conduction band separation (IEFL 0.55 eV for 1n053Ga047As; EEUL = 0.33 eV for GaAs). In this paper, we present Monte Carlo simulation results demonstrating the efficacy of the extended velocity overshoot approach for reducing transit times across the collector for a number of 1n053Ga047As collector structures.

Paper Details

Date Published: 1 August 1990
PDF: 9 pages
Proc. SPIE 1288, High-Speed Electronics and Device Scaling, (1 August 1990); doi: 10.1117/12.20908
Show Author Affiliations
Christine M. Maziar, Univ. of Texas/Austin (United States)
Mark H. Somervell, Univ. of Texas/Austin (United States)
Carl S. Kyono, Univ. of Texas/Austin (United States)


Published in SPIE Proceedings Vol. 1288:
High-Speed Electronics and Device Scaling
Lester Fuess Eastman, Editor(s)

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