Device linearity comparison of uniformly doped and delta-doped In0.52Al0.48As/In0.6Ga0.4As metamorphic HEMTs

Abstract

The uniformly doped and the delta-doped In0.52Al0.48As/In0.6Ga0.4As metamorphic high-electron mobility transistors (MHEMTs) were fabricated, and the dc characteristics and the third-order intercept point (IP3) of these devices were measured and compared. Due to more uniform electron distribution in the quantum-well region, the uniformly doped MHEMT exhibits a flatter transconductance (G(m)) versus drain-to-source current (I-DS) curve and much better linearity with higher IP3 and higher IP3-to-P-dc. ratio as compared to the delta-doped MHEMT, even though the delta-doped device exhibits higher peak transconductance. As a result, the uniformly doped MHEMT is more suitable for communication systems that require high linearity operation.