Reactively sputtered titanium nitride Schottky contacts on n-GaAs and their thermal stability

The effects of partial pressure of nitrogen during reactive sputtering of TiNx and subsequent rapid thermal annealing on the quality of TiNx/n-GaAs are analysed. Nitrogen partial pressure of 0.1 produces poor-quality contacts. Increasing the partial pressure of nitrogen to 0.3 improves the contact properties. Further increasing partial pressure of nitrogen to 0.4 causes a reduction of the barrier height while the other parameters remain almost unchanged. The possible under-stoichiometry in contacts made at a lower nitrogen partial pressure and over-stoichiometry, excess unbonded nitrogen atoms and formation of a GaAs1-xNx interfacial layer at higher annealing temperatures in contacts made at higher nitrogen pressure are used to explain the observations.