Investigation of contact mechanism and gate electrostatic control in multi-channel AlGaN/GaN high electron mobility transistors with deep recessed ohmic contact

In this paper, the ohmic contact mechanism and gate electrostatic control of a deep-recessed ohmic contact structure for multi-channel Al0.3Ga0.7N/GaN high electron mobility transistors (HEMTs) is investigated. A transmission electron microscope and an energy dispersive spectrum are utilized to inve...

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Bibliographic Details
Published in:Journal of applied physics 2022-10, Vol.132 (16)
Main Authors: Yang, Ling, Lu, Hao, Niu, Xuerui, Zhang, Meng, Shi, Chunzhou, Deng, Longge, Hou, Bin, Mi, Minhan, Wu, Mei, Cheng, Kai, Zhu, Qing, Lu, Yang, Lv, Ling, Ma, Xiaohua, Hao, Yue
Format: Article
Language:English
Subjects:
Aluminum gallium nitrides
Applied physics
Contact resistance
Electric contacts
Gallium nitrides
High electron mobility transistors
Leakage
Reduction
Semiconductor devices
Transistors
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Summary:In this paper, the ohmic contact mechanism and gate electrostatic control of a deep-recessed ohmic contact structure for multi-channel Al0.3Ga0.7N/GaN high electron mobility transistors (HEMTs) is investigated. A transmission electron microscope and an energy dispersive spectrum are utilized to investigate the ohmic contact interface mechanism. Due to a reduction of source/drain parasitic resistances and simultaneous connection of five channels by using deep-recessed ohmic contact, a large maximum drain current density and a distinct five hump feature of ultra-wider trans-conductance are achieved. More importantly, it is revealed that the downward expansion of the gate potential for the deep-recessed ohmic contact structure is much deeper than that for conventional devices. This characteristic leads to a remarkable reduction in subthreshold swing (SS) and off-state leakage, indicating an ultra-wide and high trans-conductance profile. The fabricated devices show a lower off-state drain leakage, a lower SS, and a wider gate voltage swing (40 V). Due to an enhancement of gate electrostatic control, the current collapse and electrical reliability characteristics of multi-channel Al0.3Ga0.7N/GaN HEMTs with deep-recessed ohmic contact also improve. The results presented here indicate that the multi-channel device has great potential for high current and wide bandwidth applications.
ISSN:0021-8979
1089-7550
DOI:10.1063/5.0106827