Kelvin probe force microscopy of gate stack metal alloy films

This paper describes the development of work function measurements using Kelvin probe force microscopy (KPFM) on semiconductor materials including high-κ/metal gate layers. We show how the choice of substrate and/or underlying films affects work function quantification. Other influences on work function measurement such as sample aging, humidity, and measurement mode were also studied. Finally, TiAl alloy work function measurements were compared with XPS measurements and transistor electrical characteristics for varied TiAl alloy deposition conditions and periodic monitoring.