Saturation in the transfer characteristics of (Al,Ga)As/GaAs modulation-doped field-effect transistors at 77 K
- 1 December 1984
- journal article
- Published by AIP Publishing in Applied Physics Letters
- Vol. 45 (11) , 1190-1192
- https://doi.org/10.1063/1.95093
Abstract
Modulation-doped field-effect transistors operating under large forward gate biases at 77 K have been studied both experimentally and theoretically. The theoretical analysis includes the self-consistent solution of Schrödinger’s and Poisson’s equations in the GaAs channel and includes Fermi–Dirac statistics in the GaAs and AlGaAs. A dramatic decrease in transconductance is observed at large forward gate voltages and is explained within the theory as being due to limited two-dimensional electron gas concentration and the gate voltage dependence of the concentration of electrons bound to donors in the AlGaAs. The balance of dynamics of the Fermi level versus conduction-band energy and electron occupation of the relatively deep Si donors lead to the observed saturation in drain current versus gate voltage (transfer) characteristics.Keywords
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