Micropower Microwave HFET Devices and Circuits

This work investigates the use of novel HFET§(Hetero-Junction Field Effect Transistor) devices at§microwave frequencies and at micropower supply§levels. A thorough review of current state-of-the-art§micropower circuit techniques is included and the§Reader is then guided through the intrinsic parameter§extraction methodology employed to analyse these§devices at microwave frequencies. An in-depth RF and§DC analysis based on directly extracted data from§measurements of state-of-the-art buried channel (BC)§Si/SiGe nHMODFET devices is then presented. The§results confirm the RF micropower capability of these§devices by highlighting peaks in mean carrier§mobility and transconductance within an operating§region delimited by the end of sub-threshold§operation and start of linear operation. RF§micropower capability is further confirmed by the§measured characteristics of fabricated circuits§employing these devices. The recently published KAIST§small signal RF model is also successfully fit, for§the first time, to nHMODFET characteristics measured§at micropower levels. Most of the work included in§this book has been published separately by the author§in international, peer-reviewed journals.