Effect of p-i-p/sup +/ buffer on characteristics of n-channel heterostructure field-effect transistors

The carrier concentration in heterostructure FETs (HFETs) with a p-i-p/sup +/ buffer is presented as a function of the gate bias, obtained by self-consistent one-dimensional calculation of 2-D electron density, subband levels, and electrostatic potential. These results quantify certain limitations on the range of geometrical and doping parameters and make it possible to optimize the HFET design and to compare modulation doped FET (MODFET) and doped channel HFET (DCHFET) structures. Monte Carlo simulations demonstrate that this p-i-p/sup +/ buffer drastically reduces the short-channel effects.<
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