Buffer Traps Effect on GaN-on-Si High-Electron-Mobility Transistor at Different Substrate Voltages

Yuan Lin; Min-Lu Kao; You-Chen Weng; Chang-Fu Dee; Shih-Chen Chen; Hao-Chung Kuo; Chun-Hsiung Lin; Edward-Yi Chang

doi:10.3390/mi13122140

Buffer Traps Effect on GaN-on-Si High-Electron-Mobility Transistor at Different Substrate Voltages

Micromachines (Basel). 2022 Dec 3;13(12):2140. doi: 10.3390/mi13122140.

Authors

Yuan Lin¹, Min-Lu Kao¹, You-Chen Weng², Chang-Fu Dee³, Shih-Chen Chen⁴, Hao-Chung Kuo⁴, Chun-Hsiung Lin⁵, Edward-Yi Chang^{1

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Affiliations

¹ Department of Materials Science and Engineering, National Yang Ming Chiao Tung University, Hsinchu 30010, Taiwan.
² Institute of Lighting and Energy Photonics, National Yang Ming Chiao Tung University, Hsinchu 30010, Taiwan.
³ Institute of Microengineering and Nanoelectronics, Universiti Kebangsaan Malaysia, Bangi 43600, Malaysia.
⁴ Semiconductor Research Center, Hon Hai Research Institute, Taipei 11492, Taiwan.
⁵ International College of Semiconductor Technology, National Yang Ming Chiao Tung University, Hsinchu 30010, Taiwan.
⁶ Institute of Electronics Engineering, National Yang Ming Chiao Tung University, Hsinchu 30010, Taiwan.

Abstract

Substrate voltage (V_SUB) effects on GaN-on-Si high electron mobility transistors (HEMTs) power application performance with superlattice transition layer structure was investigated. The 2DEG conductivity and buffer stack charge redistribution can be affected by neutral/ionized donor and acceptor traps. As the donor/acceptor traps are excessively ionized or de-ionized by applying V_SUB, the depletion region between the unintentionally doped (UID)/Carbon-doped (C-doped) GaN layer may exhibit a behavior similar to the p-n junction. An applied negative V_SUB increases the concentration of both the ionized donor and acceptor traps, which increases the breakdown voltage (BV) by alleviating the non-uniform distribution of the vertical electric field. On the other hand, an applied positive V_SUB causes the energy band bending flattener to refill the ionized traps and slightly improves the dynamic R_on degradation. Moreover, the amount of electrons injected into the buffer stack layer from the front side (2DEG channel/Ohmic contact) and the back side (AlN nucleation layer/superlattice transition layer) are asymmetric. Therefore, different V_SUB can affect the conductivity of 2DEG through the field effect, buffer trapping effect, and charge redistribution, which can change the electrical performance of the device.

Keywords: GaN; HEMT; breakdown voltage; charge redistribution; donor trap; dynamic on-resistance; substrate voltage.

Grants and funding

This work was financially supported by the “Center for the Semiconductor Technology Research” from The Featured Areas Research Center Program within the framework of the Higher Education Sprout Project by the Ministry of Education (MOE) in Taiwan. Also supported in part by the Ministry of Science and Technology, Taiwan, under Grant No. NSTC-110-2622-8-A49-008-SB, NSTC-111-2622-8-A49-018-SB and NSTC-111-2634-F-A49-008 as well as National Chung-Shan Institute of Science and Technology NCSIST-404-V407(111).