Studies on the Interface of TiN/n-GaAs

ABSTRACTRecent reports on refractory metal nitrides/n-GaAs Schottky contacts have demonstrated that improved electrical performance can be obtained after annealing at temperature between 750 and 850°C . It is thought that a p+-type layer should be responsible for this phenomenon, which may be generated by N or N related defects. In this paper, the role of nitrogen in SI-GaAs and n-GaAs has been investigated by Hall effect and DLTS measurements. No evidence of the formation of a p+-type layer has been observed. A deep energy level of Ec-0.36eV which is thought to be related to N and an enhanced effect of N on the density of EL2 level were observed. DLTS and SIMS techniques were used to study the interface of TiN/n-GaAs Schottky contacts. The Ti3+(3d1)/Ti2+(3d2) single acceptor level at Ec-0.21 eV was observed, but the EL2 donor level is dominant. Combining the experimental results, a discussion is made about the reasons for the improvements of electrical performance after annealing.