Numerical analysis of device performance of metamorphic In/sub y/Al/sub 1-y/As/In/sub x/Ga/sub 1-x/As (0.3/spl les/x/spl les/0.6) HEMTs on GaAs substrate

A numerical model describing the influence of InAs mole fraction on metamorphic HEMT structures (MM-HEMT) is proposed. The material properties are calculated using the Monte Carlo method, while the charge control law is calculated using a self-consistent solution of Poisson's and Schrodinger's equations. The modeling of the dc, ac, noise and high frequency performance of a device with 0.25-/spl mu/m gate length is performed using the quasi-two-dimensional (Q2D) approach. This analysis shows that an InAs mole fraction of about 0.40 is an optimum composition for manufacturing high gain, low noise amplifiers. In this range of composition, the performance of MM-HEMT structures is similar to that obtained for lattice-matched HEMTs on InP substrates.