Backgating effect in III-V MESFET鈥檚: A physical model

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• 作者：J.C. Manifacier ; R. Ardebili
• 关键词：Semi-insulating GaAs ; InP ; Backgating effect ; MOSFET ; Metal&ndash ; N&ndash ; SI&ndash ; N+ structures
• 刊名：Solid-State Electronics
• 出版年：January, 2014
• 年：2014
• 卷：91
• 期：Complete
• 页码：13-18
• 全文大小：588 K

文摘

The backgating (sidegating) effect in III-V MESFET鈥檚 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.