Majority and Minority Carrier Traps in NiO/β-Ga2O3 p+-n Heterojunction Diode

• Published in: IEEE transactions on electron devices 2022-03, Vol.69 (3), p.981-987
• Main Authors: Wang, Zhengpeng, Gong, Hehe, Meng, Chenxu, Yu, Xinxin, Sun, Xinyu, Zhang, Chongde, Ji, Xiaoli, Ren, Fangfang, Gu, Shulin, Zheng, Youdou, Zhang, Rong, Ye, Jiandong
• Format: Article
• Language: English
• Subjects: Capacitance; Carrier transport; Carrier traps; Deep level transient spectroscopy; deep level transient spectroscopy (DLTS); Diodes; Electron traps; Electronic devices; Energy levels; Energy states; Gallium oxides; Heterojunctions; Majority carriers; minority carrier traps; Minority carriers; Nickel oxides; p-n heterojunction; Photonic band gap; Schottky diodes; Transient analysis; Voltage measurement
• ISSN: 0018-9383; 1557-9646
• DOI: 10.1109/TED.2022.3143491

Identifying defects/traps is of vital importance for the implementation of high-performance Ga 2 O 3 power devices. In this work, majority and minority carrier traps in beta-gallium oxide ( \beta -Ga 2 O 3 ) have been investigated and identified by means of deep level transient spectroscopy (DLTS) in Ni/ \beta -Ga 2 O 3 Schottky barrier diode (SBD) and NiO/ \beta -Ga 2 O 3 p + -n heterojunction diode (HJD). For both diodes, a dominant energy level of majority carrier (electron) trap states is determined to be {E}_{C}- (0.75-0.79) eV with a concentration of (2.4-4.1) \times 10^{{13}} cm ^{-{3}} . Meanwhile, an additional trapping level at {E}_{V} +0.14 eV with a concentration of 1.2 \times 10^{{14}} cm ^{-{3}} yield is present in NiO/ \beta -Ga 2 O 3 bipolar HJD but absent in the Ni/ \beta -Ga 2 O 3 SBD unipolar counterpart. The detection of such minority carrier traps originates from the hole injection through trap-assisted tunneling (TAT) from \text{p}^{+} -NiO to \beta -Ga 2 O 3 . The bias- and frequency-dependent DLTS characteristics identify that such shallow-level minority carrier traps are located in the \beta -Ga 2 O 3 bulk region rather not interfacial states at the NiO/ \beta -Ga 2 O 3 heterointerface. The identification of both majority and minority carrier traps in this work may shed light on the in-depth understanding of carrier transport mechanisms in Ga 2 O 3 -based unipolar and bipolar