GaAs/(In,Ga)As, p-channel, multiple strained quantum well field-effect transistors with high transconductance and high peak saturated drain current

Abstract

GaAs/In_0.2 Ga_0.8 As structures with two paralleled 10 nm quantum wells, modulation doped from the top, bottom, and middle with Be, have been fabricated into multiple strained quantum well field‐effect transistors (MQWFET’s) with 1×150 μm² Ti/Au gates and examined both illuminated and in the dark at 300 and 77 K. Measurements on van der Pauw structures fabricated simultaneously with the transistors showed hole mobilities and sheet carrier densities to be 200, 3100, and 8040 cm²/V s, and 5.7×10¹², 1.8×10¹², and 1.5×10¹² cm⁻² , at 300, 77, and 4 K, respectively. Shubnikov–de Haas measurements made below 4 K verified the existence of a double‐channel two‐dimensional hole gas with a strain‐shifted light‐hole ground state in the quantum wells with an effective hole mass of 0.15 m_e . A representative p‐channel MQWFET showed well‐saturated common‐source output characteristics, both illuminated and unilluminated, at all measurement temperatures. Measured peak extrinsic transconductances and peak saturated drain currents for the unilluminated 1 μm device were 31 and 60 mS/mm and 27 and 67 mA/mm, at 300 and 77 K, respectively.