There is a great effort towards development of normally-off GaN heterostructure-field-effect transistor (HFET) for switching applications. Such technology can potentially have an enormous impact on the environment via minimizing the conversion losses in the electricity distribution and improvements in the hybrid cars technology. Among others, insulated gate HFETs, i.e. MOS-HFETs represent an excellent candidate for this purpose as an appropriate selection of the gate dielectric layer can provide a manipulation of the so-called surface donors, to allow the desired adjustment of the transistor’s threshold voltage (VT). Despite a fast development in this research field, a complete analytical model for the calculation and technological adjustment of VT was still missing in the literature. We proposed such a model together with separation of the relevant charges across the gate structure and explained the effect of the charges on MOS-HFET VT.
This work was carried out within the EU 7RP project HipoSwitch. The project aims the development and transfer of the technology of ‘normally-off’ power HFETs, i.e. devices with VT>0, for efficient power converters for telecom industry.
Ťapajna, M. and Kuzmík, J.: A comprehensive analytical model for threshold voltage calculation in GaN based metal-oxide-semiconductor high-electron-mobility transistors. Applied Phys. Lett. 100 (2012) 113509.
M. Ťapajna, K. Fröhlich, and J. Kuzmík, Int. Workshop on Semiconductor Devices – IWSD’12 (invited), March 5-6 2012, RCIQE, Sapporo, Japan.
M. Ťapajna and J. Kuzmík, In: Int. Workshop on Nitride Semicond., IWN’12, October 14-19 2012, Sapporo, Japan.