Analysis of Physical Mechanism for GaN Semiconductors Traps by AC Two Port Network

2023 Fiscal Year Final Research Report

• Project/Area Number: 21K04139
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 21050:Electric and electronic materials-related
• Research Institution: Saga University
• Principal Investigator: Oishi Toshiyuki 佐賀大学, 理工学部, 教授 (40393491)
• Project Period (FY): 2021-04-01 – 2024-03-31
• Keywords: 2端子対回路網パラメータ / 窒化ガリウムトランジスタ / トラップ評価 / 等価回路モデル

Outline of Final Research Achievements

Low-frequency Y parameters in the two-port network have been studied to analyze the mechanism and properties of the traps in GaN devices. The DC bias of the gate voltage was set to be 0 V, where there is two-dimensional electron gas between the GaN channel and AlGaN barrier. The DC bias of the drain voltages and the sample temperature were precisely controlled by small intervals. Furthermore, the device simulation was combined with the experimental results, and the origins of the peaks were identified. The imaginary parts of Y22 signals have the traps located in GaN and self-heating effect peaks which don’t almost depend on the temperature. Y21 signals have trap peaks in AlGaN in addition to Y22 peaks. Therefore, two-type traps and self-heating effects are divided using Y22 and Y21. The small-signal equivalent circuit with the trap circuits can be constructed using these results, and the improvement of the module performance is expected by design using the equivalent circuit.

Free Research Field

電気電子工学　電子・電気材料工学

Academic Significance and Societal Importance of the Research Achievements

窒化ガリウム（GaN）半導体は様々な分野に実用化されているが、より社会を発展させるためにはより高性能なデバイスと回路を社会実装する必要がある。GaN半導体の優れた潜在能力を引き出すためには、トラップを制御することが重要である。このため、トラップの性質や挙動を明確にし、デバイスや回路にフィードバックできる評価方法が求められる。特に次世代無線通信分野ではトラップが応答する低周波数領域での信号の振舞いが回路に大きな影響を与える。本研究では回路モデルと整合性の高い2端子対回路パラメータを使ってトラップ信号を測定することで、物理的な意味を持つトラップを回路モデルに直接組込む評価方法を研究した。