Study of the Formation Mechanism of Cu/Ge/Pd Ohmic Contact to n-Type InGaAs

Abstract

This study investigates electrical characteristics and the formation mechanism of the Cu/Ge/Pd Ohmic contact to n-type InGaAs. After annealing the contact at 250 degrees C for 20 min, Cu(3)Ge and Pd(12)Ga(5)As(2) compounds formed and Ge diffused into the InGaAs layer, achieving a heavily doped InGaAs layer with a low contact resistivity of 1 x 10(-6) Omega cm(2). Thermal stability tests were performed on the Cu/Ge/Pd Ohmic contact to InGaAs after Ohmic contact formation, showing no obvious degradation after a 72 h reliability test at 250 degrees C. The results indicate excellent electrical characteristics and thermal stability using Cu/Ge/Pd as an Ohmic contact metal to an n-InGaAs layer.