6500-V E-mode Active-Passivation p-GaN Gate HEMT with Ultralow Dynamic R<sub>ON</sub>
Jiawei Cui, Jin Wei, Maojun Wang, Yanlin Wu, Junjie Yang, Teng Li, Jingjing Yu, Han Yang, Xuelin Yang, Jinyan Wang, Xiaosen Liu, Daisuke Ueda, Bo Shen
Abstract
This work demonstrates the E-mode active-passivation p-GaN gate HEMTs (AP-HEMTs) on sapphire substrate with blocking capabilities up to 6500 V. The AP-HEMT features an active passivation (i.e. a thinned p-GaN layer) extending from the gate edge towards near the drain contact. The 2DEG under the p-GaN gate and the active passivation is fully depleted at zero gate bias, resulting in E-mode operation with a V <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">th</inf> = 0.8 V at I <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">D</inf> = 10 μA/mm. With a positive V <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">GS</inf> of 3.5 V, the AP-HEMT with L <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">GD</inf> = 77 μm presents an R <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">ON</inf> of 38.2 Ω-mm, and R <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">ON,SP</inf> of 33.62 mΩ·cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> . In the OFF-state, the active passivation is depleted from the drain side towards the gate edge. For L <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">GD</inf> = 77 μm, the AP-HEMT presents a high breakdown voltage of 6573 V, resulting in a FOM (BV <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> /R <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">ON</inf> ) of 1.29 GW/cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> that approaches the SiC limit. In the AP-HEMT, the effect of surface charges is screened by the active passivation layer, resulting in ultralow dynamic R <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">ON</inf> . For the AP-HEMT with L <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">GD</inf> = 77 μm, the measured dynamic R <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">ON</inf> /static R <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">ON</inf> is 1.15 after a 10-ms 3000-V V <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">DS-OFF</inf> stress (delay time = 150 μs) and 1.02 after a 3-s 4500-V V <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">DS-OFF</inf> stress (delay time = 300 ms). The results demonstrate that the active passivation can extend the E-mode p-GaN gate HEMT technology to kV-level applications.