Papers by Keyword: Current Collapse

Abstract: This paper reviews the state-of-the-art technologies of the normally-off GaN Gate Injection Transistor (GIT) and its applications such as inverter for motor drive and Power Factor Collection (PFC). Fundamental performances such as the current-collapse-free operation and the excellent switching performance are reviewed.

Abstract: The effect of AlGaN surface traps on breakdown voltage VB and drain current collapse in AlGaN/GaN high electron mobility transistors (HEMTs) were investigated using experimental measurement and numerical simulation. The drain current transient due to surface traps was systematically measured and analyzed, and the activation energy of a surface trap was evaluated as approximately 0.7 eV. Results from the device simulation of VB in HEMTs were in good agreement with the experimental results when assuming surface traps. The results indicate that surface traps increase VB, and induce a crucial current collapse.

Abstract: We investigated the current collapse characteristics of the fabricated MIS-HEMT with the SiO2, SiN and high-k gate insulator. TiO2 was employed as the high-k material. We found the significant drain current change in the switching characteristic when the insulator changes. The SiN MIS-HEMT showed good switching characteristic. On the other hand, the MIS-HEMTs with oxide insulator film showed large drain current reduction. We considered that the degradation of the switching characteristic is due to the current collapse.

Abstract: The current collapse of normally-off mode AlGaN/GaN/AlGaN double heterojunction field effect transistors was investigated in comparison with the normal AlGaN/GaN heterojunction filed effect transistors.

Abstract: The mechanism of drain current collapse in AlGaN/GaN high electron mobility transistors (HEMTs) was investigated. Current collapse was clearly observed for TiO2 passivated HEMTs. However, no evidence of current collapse was apparent for SiNx passivated HEMTs. This suggests that AlGaN surface traps play a major role in current collapse. The experimental results were compared with numerical device simulation results. The device simulations were performed taking into account hot electron generation and deep traps at the AlGaN surface. The simulated drain current transients were consistent with the degradation and recovery behavior of the experimental results. These results indicate that current collapse is caused by the trapping of hot electrons in deep levels at the AlGaN surface.