Threshold Voltage Bias Temperature Instability of RF MIS-HEMTs and Schottky HEMTs Under Semi-On State Stress

Threshold Voltage Bias Temperature Instability of RF MIS-HEMTs and Schottky HEMTs Under Semi-On State Stress ■

Meng-Che Tsai, Meng-Che Tsai, Ying-Chun Kuo, Ying-Chun Kuo, Hao Yu, Hao Yu, Nelson de Almeida Braga, Nelson de Almeida Braga, Yi Yang, Yi Yang, Tzu-Heng Lin, Tzu-Heng Lin, Jingtian Fang, Jingtian Fang, Wei-Tung Lin, Wei-Tung Lin, Anna Navolotskaia, Anna Navolotskaia, Barry O'Sullivan, Barry O'Sullivan, Aarti Rathi, Aarti Rathi, Amratansh Gupta, Amratansh Gupta, Sachin Yadav, Sachin Yadav, Alireza Alian, Alireza Alian, Uthayasankaran Peralagu, Uthayasankaran Peralagu, Bertrand Parvais, Bertrand Parvais, Nadine Collaert, Nadine Collaert, Tian-Li Wu, Tian-Li Wu

Abstract ■

This study comprehensively investigates the threshold voltage (Vth) instability of AlGaN/GaN MIS-HEMTs under semi-on state conditions. The effects of various temperatures and drain biases are studied. Under semi-on bias conditions, a significant negative Vth shift up to −1.0 V is observed in MIS-HEMTs with 10-nm in-situ SiN gate dielectrics, whereas Schottky HEMTs exhibit a negligible Vth shift. A gate current analysis, comparing the MIS-HEMT with the source grounded versus floating, suggests that hot electrons induce generation of holes under the semi-on state. TCAD simulations corroborate that the high electric field across the channel of the MIS-HEMT induce hot electrons and hole generation under the semi-on state; dynamic interaction of hot electrons and holes with the gate SiN/AlGaN interfacial states leads to bias temperature instability (BTI) of the Vth of the MIS-HEMT. These findings suggest that optimizing the gate dielectric and its interface with the top barrier is crucial to improve the semi-on state stability of radio-frequency (RF) MIS-HEMTs.