Fundamental material properties and substrate technology: Effects on achievable performance by compound semiconductor FET's

Two-dimensional analyses of InP and GaAs MESFET structures are used to explain relative magnitudes of parasitic element values observed in experimental InP MESFET's. Large drain-gate capacitance observed in InP is attributed mainly to substrate conduction, while large drain conductance at certain drain biases in InP is unavoidable due to large velocity dropback and large high-field diffusion in this material. Low Schottky barrier height and substrate conduction also increase gDand Cdg.