A comparative study of SiN deposition methods for millimeter-wave AlGaN/GaN HFETs

This paper describes a comparative study on device characteristics of short-gate AlGaN/GaN HFETs with extremely thin SiN films deposited by different methods on the AlGaN surfaces. SiN deposition on an AlGaN surface greatly increases ns regardless of the deposition method, and it is useful to fabricate highly-scaled GaN HFETs for high-frequency applications. However, specific device characteristics are closely related to the deposition method; therefore, a proper choice of deposition method and further optimization of the deposition conditions are important for improvements in device characteristics. AlGaN/GaN heterostructure field-effect transistors (HFETs) are excellent candidates for millimeter-wave applications in the near future.