METAL CONTACTS TO N-TYPE GAN

Contacts consisting of various single layer metals to n-type GaN have been formed and characterized. The current-voltage characteristics wer e measured for 17 different metals (Sc, Hf, Zr, Ag, Al, V, Nb, Ti, Cr, W, Mo, Cu, Co, Au, Pd, Ni, and Pt) deposited on the same epitaxial gr owth layer. The barrier height, ideality factor, breakdown voltage, an d effective Richardson coefficients were measured from those metals wh ich exhibited strong rectifying behavior. The barrier heights for thes e metal contacts were measured using current-voltage-temperature and c apacitance-voltage techniques. It was found that an increase in metal work function correlated with an increase in the barrier height. The s urface state density of GaN was approximated to be very similar to CdS and almost a factor of ten less than GaAs.