https://doi.org/10.1140/epjs/s11734-024-01459-x
Regular Article
Impact of contact properties on the performance of β-Ga2O3 solar-blind photodetector
1
National Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, 611731, Chengdu, China
2
School of Integrated Circuit Science and Engineering, University of Electronic Science and Technology of China, 61173, Chengdu, China
3
Chongqing Institute of Microelectronics Industry Technology, University of Electronic Science and Technology of China, 401332, Chongqing, China
Received:
11
September
2024
Accepted:
18
December
2024
Published online:
7
January
2025
Herein, the impact of contact properties on the performance of β-Ga2O3 solar-blind photodetectors (PDs) was comprehensively investigated by comparing pure Au and Ti/Au Metal–Semiconductor–Metal (MSM) contacts as well as varying the contact-annealing conditions. SIMS and XPS spectra reveal that there is a mutual diffusion between Ti and Ga atoms forming an interfacial layer, and that the out-diffusion of O atoms from β-Ga2O3 thin film results in the appearance of TiOx species and high oxygen deficiency at the metal/semiconductor (M/S) interface. Accordingly, the sensitivity of Ti/Au-contacted PDs, in terms of responsivity and specific detectivity, was enhanced by more than two orders of magnitude compared with Au-contacted one, which could be attributed to the combined effect of the formation of TiOx, increased electron density, lower Schottky barrier height, shrunk depletion-layer width, and larger internal gain. These effects can be further enhanced by the contact annealing in N2 atmosphere with the rise of temperature. However, the transient-response properties, especially for the recovery speed, degrade rapidly when introducing the increased contact annealing temperature, which could be attributed to continuously increasing interfacial traps as well as broadening interfacial-layer width, even leading to a persistent photocurrent at high anneal temperature. Therefore, the trade-off between sensitivity and speed in β-Ga2O3 solar-blind PDs should be carefully considered when introducing Ti transition layer and contract-annealing process.
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Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.
