AlGaN/GaN heterojunction field effect transistors (HFETs) have recently demonstrated powerhandling capabilities exceeding by almost an order of magnitude those of GaAs-pHEMTs. In addition, several groups have reported that low-noise performance of these high power devices almost matches that of the state of the art GaAs-pHEMTs, despite the relative immaturity of GaN HFET technology. A growing demand for GaN HFET parts that has been created by the recent promising performance of GaN HFETs led to the expansion of our research effort to include a smallscale production capability. Device results and run-to-run reproducibility data presented in this paper clearly demonstrate, that plasma assisted MBE is a viable tool for production of GaN HFETs on SiC wafers.Introduction Recent advances of power performance and speed of AlGaN/GaN heterojunction field effect transistors (HFETs) have surpassed the most optimistic predictions that were put forward only five years ago [1,2]. Several groups have recently demonstrated [3, 6-9] that microwave frequency power-handling capabilities of these devices exceed by almost an order of magnitude those of GaAs pHEMTs. The outstanding performance of GaN HFET's is attributed to their excellent current carrying capability and to high value of electric breakdown field in III-V nitride materials. The maximum drain saturation current density of 1.7 A per mm of gate periphery, reported for these devices [3], is almost a factor of 2 higher than the best values reported for microwave transistors fabricated in other material systems. The high value of saturation current is a consequence of high two-dimensional electron-gas (2DEG) sheet carrier density at AlGaN/GaN interface [4] and high electron drift velocity in GaN [5].An additional advantage of GaN HFETs over other microwave power devices is that high quality GaN films can be epitaxially grown on SiC, which is an excellent thermal conductor. The high thermal conductivity of the substrate is crucial for power transistors, as thermal effects ultimately limit their performance. Semi-insulating (SI) SiC is an ideal substrate for microwave power devices, because it conducts heat almost as efficiently as copper. It is no coincidence, that rapid progress in GaN HFET technology was made once large diameter SI SiC wafers became available [6].The GaN HFET is currently being developed for high-power solid-state amplifiers that will be used in a wide range of systems including future generation radar and satellite communication systems. Recent advances in GaN HFET power electronics include: continuous wave (cw) power density exceeding 9 W/mm at 8 GHz [7], cw power density exceeding 6 W/mm at 20 GHz [3], 23 W of cw power at 9 GHz from a single stage power amplifier fabricated by combining four 1 mm periphery devices