Lattice-matched In0.29Al0.71As/In0.3 Ga0.7As doped-channel FETs

Lattice-matched and dislocation-free In_0.29Al_0.71 As/In_0.3Ga_0.7As heterostructures with an improved Schottky barrier height have been realized on GaAs substrates. Through measurements of the temperature-dependent Hall effect as well as TEM analysis, we have verified the effectiveness of dislocation filtering from this metamorphic buffer, which is favorable for device application. Based on the doped-channel approach, we demonstrated a high current capability and high device performance of M-DCFETs. A g_m of 220 mS/mm and an I_ds of 400 mA/mm were obtained from a 1 μm-long gate device. An f_T of 22 GHz and an f_max of 51 GHz were also achieved from the same gate dimension. In addition, we conducted reliability testing, and found that a better performance was preserved for M-DCFETs. Metamorphic buffers provide, therefore, a very promising alternative way to achieve high performance of devices without the critical thickness limitation