Backgating effect in III–V MESFET’s: A physical model
•We report an analytical expression for the prediction of backgating effect in MESFET’s.•Excellent agreement is found with numerical drift–diffusion simulation results.•Electric field dependent mobilities are considered.•Results with a buffer layer are presented. The backgating (sidegating) effect i...
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Veröffentlicht in: | Solid-state electronics 2014-01, Vol.91, p.13-18 |
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Format: | Artikel |
Sprache: | eng |
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Zusammenfassung: | •We report an analytical expression for the prediction of backgating effect in MESFET’s.•Excellent agreement is found with numerical drift–diffusion simulation results.•Electric field dependent mobilities are considered.•Results with a buffer layer are presented.
The backgating (sidegating) effect in III–V MESFET’s devices is analyzed through the modelisation of a Metal (Schottky barrier)–N (channel)–SI (Semi Insulating)–N+ (back-gate contact) structure. Numerical and analytical results, using the drift–diffusion charge transport model, show that along the applied voltage range associated with backgating: (i) quasi space charge neutrality across most of the bulk SI layer and (ii) quasi Boltzmann equilibrium for the free electron across the reverse biased N (channel)–SI contact prevail for GaAs (SI) or InP (SI). The circumstances under which a negative bias applied on the back-gate (N+) contact will either develop across the reverse biased N–SI contact (strong backgating) or across the SI layer (negligible backgating) are described by means of a simple analytical relation as a function of the deep level parameters values. The electric field dependence of the carrier mobility (Gunn effect) produces a backgating effect with a threshold voltage. The presence of a low lifetime, buffer layer, at the N–SI interface is shown to strongly reduce it. |
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ISSN: | 0038-1101 1879-2405 |
DOI: | 10.1016/j.sse.2013.09.005 |