High-performance double delta-doped sheets Ga0.51In0.49P/In0.15Ga0.85As/Ga0.51In P-0.49 pseudomorphic heterostructure transistors

Novel double delta-doped sheet ((DS)-S-3) Ga0.51In0.49P/In0.15Ga0.85As/Ga0. 51In0.49P pseudomorphic high-electron-mobility transistors (PHEMTs) have be en fabricated successfully and studied. A wide-gap Ga0.51In0.49P Schottky l ayer and a (DS)-S-3 structure are used to improve device performance. Furth ermore, an airbridge-gate structure is employed to achieve good de and RF p erformances. For a 1 mu m gate length device, a high gate-to-drain breakdow n voltage over 35 V, an available output current density up to 615 mA mm(-1 ), a maximum transconductance of 110 mS mm(-1) and a high de gain ratio of 487 are obtained. On the other hand, the maximum values of unity current ga in cut-off frequency f(T) and maximum oscillation frequency f(max) are 19.5 and 40.5 GHz, respectively. The output power of 15.6 dB m (363 mW mm(-1)), power gain of 5.6 dB, power added efficiency (PAE) of 37% and drain effici ency (DE) of 51% are obtained at an input power of 10 dB m and the measured frequency of 2.4 GHz.