Investigation on Capacitance Collapse Induced by Secondary Capture of Acceptor Traps in AlGaN/GaN Lateral Schottky Barrier Diode

Abstract

In this study, a dedicated dynamic measurement system was used to investigate the transient capacitance and recovery process of AlGaN/GaN lateral Schottky barrier diodes (SBDs). With the consideration of acceptor traps in the C-doped buffer, the C-V characteristics and transient capacitance were measured and analyzed, and the results were simulated and explained by Silvaco TCAD (technology computer aided design). The ionization of acceptor traps and the change of electric potential were monitored in transient simulation to investigate the origin of the capacitance collapse in the SBD. The results suggest the significant impact of traps in the GaN buffer layer on the capacitance collapse of the device, and the secondary capture effect on the variation of acceptor ionization. Based on the study of transient capacitance of SBD, this work could be extended to the Miller capacitance in high electron mobility transistor (HEMT) devices. Moreover, the report on the stability of capacitance is essential for GaN devices, and could be further extended to other aspects of device research.

Elucidating the Gain Mechanism in PbS Colloidal Quantum Dot Visible–Near-Infrared Photodiodes

“…These trap states originated from the oxidation of PbS-EDT films (acceptor doping) fabricated under an ambient environment and making air exposure before electrical measurements. ,, Oxygen is expected to create acceptor states on the PbS CQD films, , and the negative electricity center is formed by thermal ionization at room temperature or under a high electric field in the fully depleted junction (Figure S5). Accumulation of trapped holes in the PbS-EDT layer builds up a high electric field at the PbS-EDT/Au interface, causing a large band bending. , The light capacitance–voltage ( C – V ) measurement verifies the existence of such accumulated charges (Figure S6). Additionally, the dominant 1/ f noise at low frequency in the device suggests the existence of the random trapping and emission of carriers at the trap centers (Figure S7).…”

“…19,49,50 Oxygen is expected to create acceptor states on the PbS CQD films, 51,52 and the negative electricity center is formed by thermal ionization at room temperature 53 or under a high electric field in the fully depleted junction (Figure S5). 54 Accumulation of trapped holes in the PbS-EDT layer builds up a high electric field at the PbS-EDT/Au interface, causing a large band bending. 34,35 The light capacitance−voltage (C−V) measurement verifies the existence of such accumulated charges (Figure S6).…”