The role of unintentional acceptor concentration on the threshold voltage of modulation-doped field-effect transistors

A strong-inversion, depletion-layer model of the threshold voltage for MODFETs has been used to assess the role of unintentional acceptor doping. For concentrations less than 10/sup 13/ cm/sup -3/, acceptor doping has little effect on the threshold voltage. As acceptor density increases, the GaAs depletion-layer charge contribution will dominate, causing the threshold voltage to exceed the low-density value by as much as 1.4 V at acceptor densities approaching 10/sup 17/ cm/sup -3/.<
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