Extraction of Dynamic Threshold Voltage in Resistive Load Hard Switching Operation of Schottky-Type p-GaN Gate HEMT

• Published in: IEEE electron device letters 2022-10, Vol.43 (10), p.1720-1723
• Main Authors: Hwang, Injun, Oh, Jaejoon, Hwang, Sun-Kyu, Kim, Boram, Park, Jun Hyuk, Kim, Joonyong, Kim, Jongseob
• Format: Article
• Language: English
• Subjects: Aluminum gallium nitrides; Current measurement; Depletion; Dynamic threshold voltage; gallium nitride (GaN); Gallium nitrides; HEMTs; High electron mobility transistors; High voltages; high-electron mobility transistor (HEMT); Hot electrons; Logic gates; p-GaN gate HEMT; Probes; Schottky gate; Switches; Switching; Threshold voltage; Transient analysis; Voltage measurement
• ISSN: 0741-3106; 1558-0563
• DOI: 10.1109/LED.2022.3200027

Threshold voltage (VTh) drift of Schottky-type p-GaN gate high-electron mobility transistor (HEMT) was analyzed under high-voltage and hard switching conditions with a resistive load (R-Load). To overcome the distortion in the drain current (ID) - gate voltage (VG) curve caused by the internal drain capacitance (IDisp) charging current during the switching transients, a method is presented to accurately measure dynamic VTh through appropriate correction of IDisp. The dynamic variation of VTh was tracked with a gate-drive rise/fall times of 200 ns. During the switching operation, VTh increases rapidly at the beginning and then saturates at a stable value. This is attributed to the gate forward current during turn-on that increases the hole depletion of the p-GaN gate through the AlGaN barrier. The dynamic VTh increases linearly at a rate of 40% with the increase of gate turn-on voltage. VTh is independent of duty cycle but minorly increases with frequency at high voltages, suggesting that channel hot electrons be injected into the AlGaN barrier and p-GaN.