The 4H-SiC Pt recessed gate metal-semiconductor field-effect transistor (MESFET) was fabricated by reactive ion etching (RIE) for device isolation. The device exhibited a pinch-off voltage of -9 V, transconductance (g,) of 19.2 mS/mm, and gate breakdown voltage of -115 V at room temperature. The characteristics of this MESFET were investigated at high temperatures. It was shown that the MESFET can operate at 560 degrees C. The time dependence of the I(DS) of a MESFET was also investigated at 400 degrees C in an At atmosphere. The change of I(DS) (V(G)=0V) was less than 5%, for the duration of 200 h. (c) 2008 Elsevier B.V. All rights reserved.