50-nm T-Gate InAlAs/InGaAs Metamorphic HEMTs With Low Noise and High fT Characteristics

We report 50-nm T-gate metamorphic high-electron mobility transistors (MHEMTs) with low noise figure and high characteristics. The 30 mumtimes2 MHEMT shows a drain current density of 690 mA/mm, a g_m,max of 1270 mS/mm, an f_T of 489 GHz, and an of 422 GHz. In the frequency range of 59-61 GHz, the noise figure is less than 0.7 dB, and the associated gain was greater than 9 dB at a drain voltage of 1.3 V and a gate voltage of -0.8 V. To our knowledge, the MHEMT shows the best performance in terms of and noise figure among GaAs-based HEMTs.