Modeling and characterization of photovoltaic and photoconductive effects in insulated-gate field effect transistors under optical excitation

• Published in: Solid-state electronics 2021-12, Vol.186, p.108139, Article 108139
• Main Authors: Yoo, Han Bin, Kim, Haesung, Ryu, Ji Hee, Park, Jingyu, Bae, Jong-Ho, Choi, Sung-Jin, Kim, Dae Hwan, Kim, Dong Myong
• Format: Article
• Language: English
• Subjects: MISFET; Modeling; MOSFET; Photoconductive; Photonic response; Photovoltaic; Separation; TFT
• ISSN: 0038-1101; 1879-2405
• DOI: 10.1016/j.sse.2021.108139

•We modeled photonic response as a combination of the PVE and the PCE in MISFETs.•We defined the PVE as the effective substrate potential change (ΔVSub,eff = VPVE).•We defined the PCE as the effective surface potential change (VPCE). Under optical illumination of metal–insulator-semiconductor field effect transistors with insulated gate structure (MISFETs including MOSFETs and TFTs), photo-generated electron-hole pairs (ehp’s) cause the photovoltaic effect (PVE) and the photoconductive effect (PCE) in the electrical characteristics of MISFETs. In the modeling and characterization of MISFETs under optical excitation for both optical sensing and/or electro-optical characterization of traps through photonic C-V and I-V responses, it is necessary to separate the PVE from the PCE in MISFETs. In this letter, we report the modeling and separate characterization of the PVE from the PCE in MISFETs applicable to MOSFETs and TFTs. We confirmed the proposed model and the technique through experimental results adopting the different substrate contact configurations and optical power of the device under characterization. As a result, the effective surface potential change for the PCE (VPCE) and the effective substrate potential change for the PVE (VPVE) could be quantitatively extracted.