Development of highly-sensitive ultraviolet sensing method using diamond

本项目的目的是开发一种利用金刚石半导体作为深紫外光探测器的高灵敏度紫外光传感方法，其响应能量大于4.4 eV。为此，研制了肖特基光电二极管和金属-半导体-金属(MSM)二极管。我们首次利用热稳定的过渡金属碳化物和氮化物肖特基接触研制了热稳定、高灵敏度的肖特基光电二极管。三年来的研究结果如下：(1)研制了过渡金属碳化物、WC、肖特基接触和退火态Ti/WC欧姆接触肖特基光电二极管。DUV(220 Nm)与可见光(630 Nm)的分辨比高达10~(-6)，经550℃热处理3h后，光电二极管的光响应特性几乎没有变化。(2)研制了过渡金属氮化物、HFN、肖特基接触和退火的Ti/WC欧姆接触肖特基光电二极管。该光电二极管的高速响应时间小于0.3 S，对紫外光和可见光的分辨比为10 6，同时具有高达500℃的热稳定性。(3)为了将金刚石传感器应用于火焰传感器，研制了全封装键合光电二极管器件。在与ANTEC公司的验证中，首次展示了使用钻石DUV传感器的火焰探测/报警系统。

The purpose of this project is to develop a highly-sensitive ultraviolet light sensing method using diamond semiconductor as deep-UV (DUV) photodetector with response energy larger than 4.4 eV. For this purpose, Schottky photodiode and metal-semiconductor-metal (MSM) diode were fabricated. We developed thermally stable, highly sensitive Schottky-type photodiode for the first time by using thermally stable transition metal carbide and nitride Schottky contacts. The results obtained for three years are as follows.(1)The Schottky photodiode with the transition metal carbide, WC, Schottky contact and annealed Ti/WC Ohmic contact was developed. The discrimination ratio between the DUV (220 nm) and visible light (630 nm) was as large as 10^6. The photoresponse properties of the photodiode was almost unchanged after thermal annealing up to 550 C for 3 h.(2)The Schottky photodiode with the transition metal nitride, HfN, Schottky contact and annealed Ti/WC Ohmic contact was developed. This photodiode showed the high speed response time shorter than 0.3 s and the discrimination ratio between the DUV and visible light of 10^6 and simultaneously revealed the thermal stability up to 500 C.(3)In order to apply the diamond sensor to the flame sensor, fully-packaged and bonded photodiode devices were fabricated. In corroboration with ANTEC Co.,the flame detection/alarm system using the diamond DUV sensor was demonstrated for the first time.