Improved tolerance to operation temperature in δ-doped inverted HFETs

Abstract

Inverted delta doping in HFETs offers the possibility of enhanced performance. It makes possible the development of very high frequency/speed and power transistor circuits. The operating temperature range and δ-doping concentration are critical, because they strongly affect the device ability to confine the current flow into the fast quantum well channel. In this study, the effect of temperature and δ-doping concentration on the performance of inverted HFETs is analysed by means of numerical simulations. The results are analytically and qualitatively discussed, showing how to fine-tune the δ-doping concentration from medium to high temperatures. Comparisons with a similar conventional HFET demonstrate a better tolerance to temperature variations in the inverted ones.