GaN基紫外探测器的电子辐照效应

Effect of electron irradiation on the GaN-based p-i-n UV detector

用能量为0.8 MeV的电子对非故意掺杂的GaN材料进行了辐照,光致发光谱(PL谱)表明,辐照使PL谱的强度随电子注量依次降低,且主发光峰蓝移,在注量较高时,在3.36 eV附近,出现新的发光峰。制备了SiN/GaN的MIS结构,并对其进行电子辐照,通过测量C-V曲线计算得到SiN/GaN之间的界面态随着电子辐照注量的增加而增加。制备了GaN基p-i-n结构可见盲正照射紫外探测器并进行电子辐照,测量了辐照前后器件的I-V曲线和光谱响应曲线。实验表明,小注量的电子辐照对器件的反向暗电流影响不大,当电子注量≥5×1016 n/cm2时才使器件的暗电流增大一个数量级。辐照前后器件的光谱响应曲线表明,电子辐照对器件的响应率没有产生明显的影响。利用GaN材料和MIS结构的辐照效应分析了器件的辐照失效机理。

Electrons with different fluences were radiated on the GaN material. The photoluminescence studies of the irradiated sample showed the intensity of PL was reduced and a blueshift were observed after irradiation. One radiation-induced formation of new optically active centers appeared after higher fluence. Then the SiN/GaN metal insulator semiconductor diodes were fabricated to study the effect on the electrical properties of SiN/GaN interface. The results showed that the electron irradiation induces new interface density between the SiN and GaN. GaN-based UV photodetectors were fabricated and irradiated with electron. I-V characterization and response spectrum of the detectors were measured before and after irradiation to analyze the irradiation effect. After higher electron fluence of irradiation, the reverse leakage current is enlarged with one order. The response spectrum after irradiation is slightly smaller than before irradiation which shows the radiation hardness of the AlGaN photodetector. The failure mechanism of irradiated detectors was analyzed.