EVALUATION OF THE RadFET RADIATION SENSOR PERFORMANCE IN 18 MV-EXTERNAL BEAM

• Main Authors: Ayşegül Kahraman, Berk Morkoç, Dinçer Yeğen, Ercan Yılmaz
• Format: Article
• Language: English
• Published: Bursa Uludag University 2019-12-01
• Series: Uludağ University Journal of The Faculty of Engineering
• Subjects: radfet; radiation response; radiotherapy; radyasyon cevabı; radyoterapi
• Online Access: https://dergipark.org.tr/tr/pub/uumfd/issue/49627/558166

The radiation response of RadFET irradiated with 18 MV X-rays emitted from a linear accelerator was examined on threshold voltage shifts and trap densities. The measured threshold voltages were compared before and after irradiation. Trap densities calculated using various techniques in the gate oxide and oxide/silicon interface were interpreted. The ΔVth – D graph showed excellent linearity of up to just about 2 Gy. The RadFETs response to radiation started to deviate from linearity after 2 Gy due to increasing oxide trapped charges induced by electric field screening. The experimental outcomes are in good accordance with the fitting function given for RadFETs. Fixed and switching traps formed by irradiation were investigated. The density of the fixed traps was significantly higher than the density of the switching traps. From the threshold voltages measured under zero gate voltage in a certain time interval, the percentage fading range was calculated as 0.004-1.235%.