1 DIAMOND FIELD EFFECT TRANSISTORS Stephen A.O. Russell*, Salah Sharabi*, Alex Tallaire†, Helen McLelland* and David A.J. Moran* * School of Engineering, University of Glasgow, Glasgow, United Kingdom. Contact: s.russell.1@research.gla.ac.uk, Tel: +44 (0)141 330 3374 † LIMHP-CNRS, Université Paris 13, 99 Avenue Jean-Baptiste Clément, 93430 Villetaneuse, France ABSTRACT High-quality single crystal diamond has been used to demonstrate the RF performance of hydrogen- terminated diamond field effect transistors of varying gate lengths; this includes the first data on a sub- 100nm diamond transistor. The RF performance for 220nm, 120nm and 50nm gate length transistors was extracted and a cut-off frequency of 55 GHz was measured for the 50nm device. This is the highest value yet reported for any diamond based transistor. This significant increase can be attributed to the quality of the material, improved diamond growth techniques and device scaling. 1. INTRODUCTION Diamond has long been seen as the perfect material for high power electronics, with a material breakdown field of 10 MVcm -1 for pure single crystal diamond and thermal conductivity >2000 Wm -1 K -1 [1]. The large bandgap associated with diamond of 5.47eV makes it suitable for high voltage operation. If current difficulties with processing could be overcome then diamond could fill requirements for a niche market requiring robust high power and high frequency electronics for operation in harsh environments. Figure 1: Plot demonstrating the superior material qualities associated with diamond Along with power performance diamond can also offer competitive frequency performance. Velocity saturation occurs at ~ 1x10 7 cm.s -1 and low field mobility can reach up to 4500 and 3800 cm 2 V -1 s -1 for electrons and holes respectively [1].