Application of the MgZnO-based metal-semiconductor-metal ultraviolet photodetector grown by Atomic Layer Deposition

• Main Authors: Kuen-TaiHuang, 黃堃泰
• Other Authors: Ching-Ting Li
• Format: Others
• Language: zh-TW
• Published: 2013
• Online Access: http://ndltd.ncl.edu.tw/handle/82717388868722025294

碩士 === 國立成功大學 === 微電子工程研究所碩博士班 === 101 === In this study, the ZnO thin film which has high quality and uniformity was grown at low temperature by atomic layer deposition system. The diethylzinc, Bis(cyclopentadienyl) magnesium and water were used as precursors, and then varied the pulse time of precursors and substrate temperature to have low defect and carrier concentration of the ZnO thin film. Moreover, the optical energy bandgap of the MgZnO changed by various doping amounts of magnesium, and applied to the metal-semiconductor- metal ultraviolet photodetector, which cut-off wavelength was lower than 370nm. This study was divided into two parts. At first, to have best quality of ZnO thin film by varied the substrate temperature. According to the window of self-limiting, the substrate temperature from 150℃ to 200℃ were self-limiting in atomic layer deposition system. The ZnO thin film has fastest deposition rate of 1.64Å/cycle and highest electron concentration about 8.27×1019cm-3 at 200℃. However, it has lowest electron concentration of 5.6×1017cm-3 and deposition rate of 1.06Å/cycle lower when the substrate temperature at 100℃. The MgZnO thin film changed the Mg contents by various ratio of ZnO and MgO. In this study, the MgZnO which grown at 100℃ and 350℃ with ratio of 9:1 were applied into metal-semiconductor-metal ultraviolet photodetector. The dark current were 1.72×10-9A and 1.67×10-4A under 5V bias, respectively. The metal-semiconductor-metal ultraviolet photodetector which deposited at 100℃ has lower dark current. Besides, under the light power of 38.02μW and 5V bias at the wavelength of 340nm, the light-dark current ratio and UV-visible rejection ratio (R340/R450) of device were 1.35×103 and 1.38×103, respectively.