Fabrication High-Temperature 4H-SiC Schottky UV Photodiodes by O<sub>2</sub> Plasma Pre-Treatment Technology
Fengyu Du, Qingwen Song, Zeyulin Zhang, Xiao-Yan Tang, Hao Yuan, Chao Han, Chunfu Zhang, Yimen Zhang, Yuming Zhang
Abstract
In this letter, an ultrahigh-temperature 4H-SiC Schottky ultraviolet (UV) photodiode (PD) using oxygen plasma pre-treatment (OPT) technology has been successfully fabricated and characterized. The PD has a high Schottky barrier height (SBH) of 1.94 eV. It shows excellent tolerance to extreme temperature with a dark current of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$2.7\times 10\,\,^{\mathbf {-8}}$ </tex-math></inline-formula> A at −25 V and 600 °C. Under UV illumination, a record operating temperature of 600 °C is realized for the first time (PDCR = 3.5 at 600 °C, −25 V). Of note, the fabricated PD exhibits high responsivity that increases with the operating temperature from 0.17 A/W at room temperature (RT) to 0.52 A/W at 600 °C, at −25 V and 275-nm. Moreover, an expeditious response time of ms level is also realized from RT to 600 °C. These results demonstrate that the proposed 4H-SiC Schottky PD is advantageous for high-temperature UV-related applications.