Temperature-Dependent Dynamic Degradation of Carbon-Doped GaN HEMTs

• Published in: IEEE transactions on electron devices 2021-07, Vol.68 (7), p.3290-3295
• Main Authors: Gu, Yitian, Wang, Yangqian, Chen, Jiaxiang, Chen, Baile, Wang, Maojun, Zou, Xinbo
• Format: Article
• Language: English
• Subjects: Activation energy; Beta decay; Carbon-doped GaN; Cryogenic temperature; cryogenic temperatures; Current carriers; Degradation; dynamic characteristics; Electron capture; Emission analysis; Gallium nitrides; GaN high electron mobility transistor (HEMT); HEMTs; High electron mobility transistors; Logic gates; low-temperature electronics; MODFETs; Potential barriers; Pulse measurements; Room temperature; Semiconductor device measurement; Silicon substrates; Stress measurement; Temperature; Temperature dependence; Threshold voltage; Time dependence; Transient analysis
• ISSN: 0018-9383; 1557-9646
• DOI: 10.1109/TED.2021.3077345

Temperature-dependent dynamic degradation was investigated for C-doped GaN high electron mobility transistor (HEMT) from 300 to 20 K. Pulsed {I} - {V} measurements with various OFF-state quiescent bias voltages revealed that current collapse (C.C.) induced by charge-trapping effect at room temperature was greatly suppressed and monotonously declined as decreasing temperatures. This was attributed to reduced number of electrons which were injected into the C-doped layer and capable of overcoming capture potential barrier. Drain current transient measurements were employed to investigate temperature-dependent and time-resolved carrier capture/emission process. Based on the extracted time constants, an activation energy of 0.36 eV was identified for the electron capture process. For carrier emission process, both current-based and capacitance-based transient analysis indicated an activation energy around 0.20 eV. Furthermore, the traps were confirmed to be located in the C-doped layer by varying the pulse stimulus in deep-level transient spectroscope (DLTS). The measurement results showed that C-doped HEMTs grown on Si substrates exhibited high-saturation current, stabilized threshold voltage, and minor C.C. at cryogenic temperatures, particularly in comparison with those at room temperature.