IEDM

Session 33: Power Devices Development of GaN Power Devices Technologies

Wednesday, December 6
Imperial Ballroom A
Co-Chairs: Martin Kuball, University of Bristol
Gaudenzio Meneghesso, University of Padova

9:05 AM
33.1 Smart GaN Platform: Performance & Challenges (Invited), C.-L. Tsai, Y.-H. Wang, M.-H. Kwan, P.-C. Chen, F.-W. Yao, S-C. Liu, J.-L. Yu, C-L Yeh, R.-Y. Su, W. Wang, W.-C. Yang, K.-Y. Wong, Y.-S. Lin, M.-C. Lin, H.-Y. Wu, C.-M. Chen, C.-Y. Yu, C.-B. Wu, M.-H., Chang, J.-S. You, T.-M. Huang, S.-P. Wang, L.Y. Tsai, Chan-Hong Chern, H.C. Tuan and A. Kalnitsky, Taiwan Semiconductor Manufacturing Company

This paper explores the next stage of GaN power devices with 2 levels integration of peripheral low voltage active and passive devices. The 1st level consists of protection/control/driving circuits, which potentially improve the performance and overcome the challenges to the power devices. (The 2nd level integration has proposed high-low side on-chip integration on 100V technology platform). The challenge of channel modulation due to substrate bias sharing is effectively eliminated by the invented new scheme. The system efficiency of DC-DC buck converter using such scheme is enhanced with lower on-state resistance and good stability.

9:30 AM
33.2 Reverse-Bias Stability and Reliability of Hole-Barrier-Free E-mode LPCVD-SiNx/GaN MIS-FETs, M. Hua, J. Wei, Q. Bao, J. He, Z. Zhang, Z. Zheng, J. Lei and K. J. Chen, The Hong Kong University of Science and Technology

With limited hole-generation, E-mode n-channel LPCVD-SiNx/GaN MIS-FET delivers small NBTI even without a hole-barrier. In reverse-bias stress, the SiNx gate dielectric, while exhibiting a negative valance-band-offset with GaN, acts as a plug to holes. The hole-induced degradation can be greatly contained by limiting gate-bias to a few volts below VTH.

9:55 AM
33.3 Improvement of Positive Bias Temperature Instability Characteristic in GaN MOSFETs by Control of Impurity Density in SiO2 Gate Dielectric, T. Yonehara, Y. Kajiwara, D. Kato, K. Uesugi, T. Shimizu, Y. Nishida, H. Ono, A. Shindome, A. Mukai, A. Yoshioka and M. Kuraguchi, Toshiba Corporation

Positive bias temperature instability in GaN MOSFET was drastically suppressed by reducing certain impurity densities in SiO2 gate dielectric. Impurities, which formed the electron traps in SiO2, were controlled by heat treatment after SiO2 deposition, and the threshold voltage shift characteristic was improved by the reduction of the impurity densities.

10:20 AM
33.4 Evidence of defect band in carbon-doped GaN controlling leakage current and trapping dynamics, C. Koller, G. Pobegen, C. Ostermaier**, and D. Pogany*, KAI GmbH, *Vienna University of Technology, **Infineon Technologies

Carbon-doped GaN layers, crucial for GaN HEMT buffers, show in a wide temperature range non- Arrhenius thermal behavior of capacitance transients related to trapping/detrapping dynamics and of leakage current. Our model indicates that conduction via defect band controls both processes, redefining the way III-N:C containing layers should be investigated.

10:45 AM
33.5 Total Suppression of Dynamic-Ron in AlGaN/GaN-HEMTs Through Proton Irradiation, M. Meneghini, A. Tajalli, P. Moens*, A. Banerjee*, A. Stockman*, M. Tack*, S. Gerardin, M. Bagatin, A. Paccagnella, E. Zanoni, and G. Meneghesso, University of Padova, Onsemiconductor*, CMST imec/Ghent University**

For the first time, we demonstrate that proton irradiation can be an effective tool for achieving zero dynamic-Ron in GaN-based power HEMTs. Based on combined pulsed characterization, transient measurements and hard switching analysis on untreated and irradiated devices we demonstrate the following relevant results: (i) the devices under analysis show an outstanding robustness against 3 MeV proton irradiation, up to a fluence of 1.5×1014 cm-2. (ii) For fluences higher than 1013 cm-2, the devices show a substantial reduction of dynamic-Ron. At the highest analyzed fluence (1.5×1014 cm-2), dynamic Ron is completely suppressed at 600 V/150 °C, without measurable changes in the gate and sub- threshold leakage and in the threshold voltage. (iii) transient and hard switching analysis indicate the total suppression of the trap-related transients identified before radiation testing. The results are explained by considering that proton irradiation increases the leakage through the uid-GaN channel layer. This increases the detrapping rate, and leads to the suppression of dynamic-Ron at high VDS