Acoustoelectric Effect in Sezawa Mode Saw Devices on Algan/Gan/Sic Heterostructure AT 9.7 GHZ

This work investigates the acoustoelectric (AE) effect in a bufferless AlGaN/GaN-on-SiC heterostructure using SweGaN QuanFINE
^®
technology. Sezawa mode acoustic delay lines (ADLs) at 9.7 GHz demonstrate the highest frequency AE operation in GaN to date, with direct observation of voltage-dependent propagation loss and nonreciprocity without the modification to the standard monolithic mm-wave integrated circuit (MMIC) platform. We design, fabricate, and characterize both passive and active AE devices leveraging the high mobility of the 2D electron gas (2DEG), which forms the channel of high electron mobility transistors (HEMTs) optimized in this GaN-on-SiC technology. This study considers two types of AE ADLs: one with a Schottky gate for electrical control of the 2DEG carrier concentration and one with source/drain Ohmic contacts to the 2DEG to control drift velocity with a lateral electric field. Measurements show a maximum tuning of propagation loss of 50 dB/cm for -5V DC at the control gate and 30 dB/cm separation between forward and reverse acoustic waves for a 2.56 kV/cm lateral DC electric field.