Study of Schottky contacts on n-Ga _0.51 In _0.49 P by low-pressure metal-organic chemical-vapor deposition

A comprehensive study of the Schottky contacts on Ga _0.51 In _0.49 P has been made. The Ga _0.51 In _0.49 P epitaxial layer was successfully grown on the GaAs substrate by low-pressure metal-organic chemical-vapor deposition to form a lattice-matched heterostructure. Three different types of films, including single-layer metal (Pt, Ni, Pd, Au, Co, Mo, W, Cr, Ti, Al, Ta, and In), metal silicides (WSi ₂ , W ₅ Si ₃ PtSi, and Pt ₂ Si), and TiW nitrides (TiWN _X ) as the Schottky contacts metals on Ga _0.51 In _0.49 P were studied. Due to the high-band-gap nature of Ga _0.51 In _0.49 P, the Schottky contacts on Ga _0.51 In _0.49 P demonstrate good characteristics. The barrier heights range from 0.79 to 1.19 eV depending on the selection of the metals and the annealing conditions. Among single-metal films, Pt film demonstrates the best thermal stability. A barrier height of 1.09 eV and an ideality factor of 1.06 were obtained even after the Pt Schottky diode was furnace annealed at 500 °C for 30 min. For refractory compounds, the TiWN _X film with the highest nitrogen content shows the best thermal stability with a barrier height of 1.00 eV and an ideality factor of 1.04 even after high-temperature annealing at 850 °C.