1. Effects of ammonia and oxygen plasma treatment on interface traps in AlGaN/GaN metal–insulator–semiconductor high-electron-mobility transistors.
- Author
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Xu, Shuqian, Zhou, Yu, Zhang, Xinkun, Li, Qian, Liu, Jianxun, Qie, Haoran, Wang, Qingru, Zhan, Xiaoning, Sun, Xiujian, Dai, Quan, Yan, Gongzheng, Sun, Qian, and Yang, Hui
- Subjects
MODULATION-doped field-effect transistors ,OXYGEN plasmas ,METAL insulator semiconductors ,GALLIUM nitride ,ATOMIC layer deposition ,X-ray photoelectron spectroscopy - Abstract
A HfO
2 /Al2 O3 /AlN stack deposited in a plasma-enhanced atomic layer deposition system is used as the gate dielectric for GaN metal–insulator–semiconductor structures. Prior to the deposition, in situ remote plasma pretreatments (RPPs) with O2 , NH3 , and NH3 –O2 (in sequence) were carried out. Frequency-dependent capacitance–voltage (C–V) measurements reveal that for all the RPP-treated samples, the interface trap density Dit was significantly reduced compared to the sample without RPP. In particular, the NH3 -treated sample exhibits an extremely low Dit of ∼1011 cm−2 ·eV−1 from EC − 0.31 eV to EC − 0.46 eV. To characterize the interface traps at deeper levels, the transfer pulsed I–V measurement was employed further. In the energy range of EC − ET > 0.54 eV, the interface trap charge density Qit of various samples demonstrates the following order: NH3 RPP < NH3 –O2 RPP < O2 RPP < without RPP. By adjusting multiple pulse widths, the Dit derived from the Qit result matches the C–V measurement precisely. Moreover, X-ray photoelectron spectroscopy analysis of the Ga 3d core-level indicates that NH3 RPP facilitates the conversion of Ga2 O into GaN at high RF power of 2500 W, whereas O2 RPP mainly oxidizes GaN to relatively stable Ga2 O3 . Combined with the C–V and pulsed I–V measurements, it is confirmed that a strong positive correlation exists between Ga2 O and the interface traps, rather than Ga2 O3 . [ABSTRACT FROM AUTHOR]- Published
- 2023
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