TIWN SCHOTTKY CONTACTS TO N-GA(0.51)IN(0.49)P

Abstract

The study of the applicability of TiW nitrides (TiWNx) as the Schottky contact metals to the n-type Ga0.51In0.49P has been made. The Ga0.51In0.49P epitaxial layer is successfully grown on the GaAs substrate by low-pressure metalorganic chemical vapor deposition (LP-MOCVD) to form a lattice-matched heterostructure. The RF-magnetron sputtering system is utilized for nitride deposition. Thermal stability of the nitride films is studied with the aid of a rapid thermal annealing system. The material properties are characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), and Auger electron spectroscopy (AES). With sufficient nitrogen content, the Schottky contacts showed excellent electrical and physical characteristics even after a high-temperature annealing. The barrier heights, ranging from 0.81 to 1.05 eV, depend on the content of nitrogen and the rapid thermal annealing (RTA) annealing condition. The XRD and AES results indicate no interaction occurring at the TiWNx/GaInP interface of both as-deposited and annealed samples. The outstanding characteristics of the Schottky contact are attributed to the high band-gap nature of the GaInP and the incorporation of nitrogen into the TiW films.