Work function control of metal transistor gates was implemented with Al-Ni alloys. In addition to obtaining conventional capacitance-voltage (C-V) measurements to evaluate the work function, we microscopically characterized the work function distribution through scanning Maxwell-stress microscopy (SMM). The C-V curves of the Al-Ni alloys that we investigated exhibited work functions approximately between those of Al and Ni. The SMM analysis revealed that an Al-Ni alloy fabricated by the interdiffusion of a Ni/Al stack had a significant nonuniformity of the work function. This nonuniformity correlated with degradation of the C-V characteristics for interdiffused Al-Ni alloys. (C) 2005 American Institute of Physics.