Neutron irradiation effects in InP/InGaAs single heterojunction bipolar transistors

• Published in: IEEE transactions on nuclear science Vol. 47; no. 6; pp. 2551 - 2556
• Main Authors: Shatalov, A., Subramanian, S., Dentai, A.
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.12.2000; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Degradation; Devices; Doping; Emittance; Gain; Heterojunction bipolar transistors; Indium gallium arsenide; Indium gallium arsenides; Indium phosphide; Laboratories; Neutron irradiation; Neutrons; Space charge; Thyristors; Trapping; Voltage
• ISSN: 0018-9499; 1558-1578
• DOI: 10.1109/23.903807

In this paper we report the effects of epi-thermal and high energy neutron irradiation on the DC characteristics of InP/InGaAs heterojunction bipolar transistors. Significant current gain degradation and collector-emitter offset voltage V/sub CE,off/ shift are the two predominant effects observed on the devices irradiated up to /spl sim/10/sup 15/ n/cm/sup 2/. The current gain degradation is attributed to the increasing base current due to the increased recombination and tunnel-assisted trapping components. The V/sub CE,off/ shift is explained by the growing base-collector (B-C) junction current caused by the defects introduced in the B-C space charge region (SCR). High, n>2, values of the base current ideality factor are modeled using the Shockley-Read-Hall (SRH) recombination and tunnel-assisted trapping in the base-emitter (B-E) SCR. Finally, devices with the higher emitter perimeter-to-area (P/A) ratio (smaller emitter) showed less degradation than the larger devices, suggesting that the degradation is primarily due to the change of the bulk properties.