Hot Carrier Injection (HCI) Reliability of Fabricated Y-gate HEMT with Various Top Length

Abstract

Device degradation due to hot carrier injection (HCI) in different Y-gate HEMT devices is thoroughly analyzed. To further understand the HCI reliability of the Y-gate HEMT devices, the device is fabricated with AlGaN/GaN structure with different top lengths (Ltop). An HCI stress time of 6000 seconds was conducted on these devices, while Vt stability in other stress time domains, leakage current, and transconductance degradation are also discussed. We have demonstrated that increasing the LTop length could avoid the virtual gate effect and disperse the influence of the electric field under HCI stress. Furthermore, the effects of trapping in various locations, such as in the bulk SiN or AlGaN/GaN interface has been discussed. These trapping effects caused by the HCI stress might be the source of the Vth shift. Overall, The large Y-gate HEMT showed the lowest degradation of DC characteristics after the long HCI stress test.

Efficacy of back barrier engineered Π-gate InAlN/GaN high electron mobility transistors for high-power applications

“…In addition to the material engineering discussed above, several researchers have ventured into the reliability aspects of GaN HEMT devices through field plate (sunken field plate architecture [38] or drain-connected field plates [39]) or gate (Π-gates [40] or Y-gates [41]) engineering techniques. The superior hot electron reliability of Π-gates demonstrated by Latorre Rey et al [40] for depletion mode devices, and further extended by Sehra et al [42] for the enhancement mode devices, suggests the possibility of improving both the thermal management and leakage characteristics of thin-barrier GaN HEMT devices.…”