High-linearity on-chip GaN-on-Si temperature sensors based on an E-mode-compatible process

In this work, we present GaN-on-Si on-chip temperature (T) sensors and ICs based on field-effect rectifiers (FERs) using an e-mode-compatible process. The single-FER T sensor presents a high sensitivity of 3.57 mV/K and a high linearity with R2 values up to 0.997, with a positive temperature coefficient (PTC). This is improved from the existing devices with negative temperature coefficients, thanks to the combined PTCs of the turn-on voltage (VON) and resistance (RON) of the device. The performance is further enhanced by ICs cascading FERs, showing a proportional enhancement of sensitivity vs the number of cascaded FERs (NFER) and leading to a sensitivity as high as 11.76 mV/°C. This scheme also leads to a significant enhancement in linearity, up to 0.999 and beyond 0.998 in a wide range of the input current (IIN). In addition to the wide use of GaN FERs, the proposed approach yields a high-performance and low-cost T-sensing solution for power GaN devices to enable better system performance and reliability.