Schottky barrier heights of In0.5(AlxGa1−x)0.5P (0≤x≤1) lattice matched to GaAs

Abstract We report a systematic investigation of the Schottky characteristics for the entire aluminum composition of In 0.5 (Al x Ga 1− x ) 0.5 P for the first time, using current–voltage measurements. The n-type Schottky barrier height φ bn has a minimum value of 0.85 eV at x =0 and a maximum value of about 1.0 eV at the direct–indirect crossover point ( x =0.55). With further increase of Al composition, φ bn decreases to 0.94 eV at x =1.0. The improved Schottky barrier height provides In 0.5 (Al x Ga 1− x ) 0.5 P FETs, such as MESFETs and HEMTs, an additional advantage for power applications due to the reduced gate leakage current. We also found that both n-type and p-type Δ φ b = φ b (In 0.5 (Al x Ga 1− x ) 0.5 P)− φ b (In 0.5 Ga 0.5 P) agree very well with their Δ E C and Δ E V , respectively, for the entire Al composition range. This general correlation can be most appropriately explained by Tersoff's “intrinsic state pinning” model.