Ohmic contact to n-GaN with TiN diffusion barrier

The formation of n-GaN/Ti ohmic contacts with TiN diffusion barriers has been investigated by electrical measurements, x-ray diffraction and SIMS. It has been shown that the onset of the ohmic behaviour is associated with the thermally induced phase transformation of Ti into TiN at the GaN/Ti interface. It is suggested that the process is accompanied by an increase in the doping level in the semiconductor subcontact region. The presence of a TiN barrier is found to inhibit excessive decomposition of GaN and to confine the reaction between n-GaN and Ti.