Presentation Information
[23p-31A-13]Traps in p-Cu2O/n-Ga2O3 heterojunction diodes studied by deep level transient spectroscopy
〇Yun Jia1, Aboulaye Traore1, Ryo Morita1, Fenfen Fenda Florena1, Muhammad Monirul Islam1, Takeaki Sakurai1 (1.Univ. of Tsukuba)
Keywords:
Ultra Wide bandgap semiconductor,Deep level transient spectroscopy,Defect
In this work, the defect state properties of two Cu2O/β-Ga2O3 pn heterojunction diodes based on different Cu2O thin film quality have been studied and identified through deep-level transient spectroscopy (DLTS). For both diodes, a bulk defect energy level positioned approximately 0.24 eV above the Cu2O valence band related to Cu-di-vacancy is detected. The diode with Cu2O thin film formed at room temperature via sputtering showed higher defect concentrations compared to the one formed at 600°C, aligning with observed differences in Cu2O thin film quality. Meanwhile, interface states, ranging from 0.6 to 0.8 eV below the Ga2O3 conduction band with an estimated interface density of approximately 4×1012 cm-2/eV were observed in the diode formed at room temperature, absent in the 600°C one. The elevated sputtering temperature likely ameliorated oxygen vacancies at the β-Ga2O3 surface, enhancing interface quality in the latter. Additionally, a discernible defect energy level, denoted as E1 and situated roughly 0.55 eV below the Ga2O3 conduction band, was detected as a non-uniform bulk defect in β-Ga2O3 layer far from the interface at a depth between around 500 and 800 nm. Furthermore, an additional bulk trapping level at EV+0.16 eV was exclusively found in the β-Ga2O3 of the diode with Cu2O thin film formed at 600°C. This defect might contribute to the observed trap-assisted space charge limited current (SCLC) or/and variable range hopping (VRH) leakage current mechanisms in this diode.