Room temperature hall mobilities above 1900cm2/Vs in MBE-grown AlGaN/GaN HEMT structures

Air AlGaN/GaN high electron mobility transistor (HEMT) structure has been grown by plasma-assisted molecular beam epitaxy (MBE) on a free-standing hydride vapour phase epitaxy-grown GaN substrate with a threading dislocation density of similar to8 x 106 cm(-2). A room temperature Hall mobility of 1920 cm(2)/V s with a street carrier density of 0.91 x 10(13) cm(-2) was measured. This is the highest room temperature electron mobility reported for an MBE-grown AlGaN/GaN structure. HEMTs fabricated on this material displayed excellent pinch-off. low gate leakage currents, and an off-state breakdown of 90 V.