Monte Carlo study of kink effect in isolated-gate InAs/AlSb high electron mobility transistors
Journal article, 2010

A semiclassical two-dimensional ensemble Monte Carlo simulator is used to perform a physical analysis of the kink effect in InAs/AlSb high electron mobility transistors (HEMTs). Kink effect, this is, an anomalous increase in the drain current I-D when increasing the drain-to-source voltage V-DS, leads to a reduction in the gain and a rise in the level of noise, thus limiting the utility of these devices for microwave applications. Due to the small band gap of InAs, InAs/AlSb HEMTs are very susceptible to suffer from impact ionization processes, with the subsequent hole transport through the structure, both implicated in the kink effect. The results indicate that, when V-DS is high enough for the onset of impact ionization, holes thus generated tend to pile up in the buffer (at the gate-drain side) due to the valence-band energy barrier between the buffer and the channel. Due to this accumulation of positive charge the channel is further opened and I-D increases, leading to the kink effect in the I-V characteristics and eventually to the device electrical breakdown. The understanding of this phenomenon provides useful information for the development of kink-effect-free InAs/AlSb HEMTs.





impact ionization






Beatriz G. Vasallo

University of Salamanca

H. Rodilla

University of Salamanca

T. Gonzalez

University of Salamanca

Giuseppe Moschetti

Chalmers, Microtechnology and Nanoscience (MC2), Microwave Electronics

Jan Grahn

Chalmers, Microtechnology and Nanoscience (MC2), Microwave Electronics

J. Mateos

University of Salamanca

Journal of Applied Physics

0021-8979 (ISSN) 1089-7550 (eISSN)

Vol. 108 9 094505

Semiconductor Nanodevices for Room temperature THz Emission and Detection (ROOTHz)

European Commission (EC) (EC/FP7/243845), 2010-01-01 -- 2013-01-31.

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Physical Sciences



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