设计和制备了吸收层和倍增层分开的4H-SiC穿通型雪崩紫外光电探测器.设计器件的倍增层和吸收层厚度分别为0.25和1μm.采用multiplejunctionter mination extension(MJTE)方法减少器件的电流集边效应和器件表面电场.对器件的暗电流、光电流和光谱响应进行了测量.器件在55V的低击穿电压下获得了一个高的增益(>104);穿通前器件暗电流约为10pA数量级;0V偏压下器件光谱响应的紫外可见比大于103.光谱响应的峰值波长随反向偏压的增大而向短波方向移动,在击穿电压附近光谱响应的峰值波长移到210nm,此波长远远小于在0V时的响应峰值.结果显示器件在紫外光探测中具有优良的性能.A 4H-SiC avalanche photodetector(APD)with separate absorption and multiplication layers was designed and fabricated.The thicknesses of the absorption and multiplication epilayers were designed as 0.25 and 1μm,respectively.A multiple junction termination extension(MJTE)was used to eliminate the electric field crowding effect at the edge and to reduce the surface electric field.Dark current,photocurrent,and spectral responsivity were measured.High gain(>104)was achieved at a low breakdown voltage,and the dark current was on the order of about 10pA before device was punched through.The ratio of responsivity at 260nm to that at 380nm was higher than 103.A new phenomenon was observed in its spectral responsivity.The response wavelength peak shifted to shorter wavelength as the reverse bias was increased.Near breakdown voltage the peak of the response wavelength was located at 210nm,which was shorter than that at 0V.These results show that the samples have good performance for ultraviolet detection
