MSM(金属-半导体-金属)型光电探测器的较低寄生电容和高带宽的特点使得其应用广泛,可用于空间通信、遥感等多方面,但暗电流偏大仍是制约其发展的重要因素.为此,本文研制了100×100 μm2 面积的InGaAs-MSM光电探测器,通过设计InAlGaAs/InGaAs短周期超晶格和InAlAs肖特基势垒增强结构,将器件暗电流密度降至0.6 pA/ μm2 (5 V偏置),改善了目前同类器件的信噪比.对器件光电参数进行了表征:3dB带宽6.8 GHz,上升沿58.8 ps,1550 nm波段响应度0.55 A/W,光吸收区域外量子效率88%.分析了短周期超晶格和肖特基势垒增强层对暗电流的抑制机理.

MSM(Mental-Semiconductor-Mental)photodetector has been widely used for its low capacitance and high bandwidth.For example,it can be used for space communication,remote sense and so on.But the development of MSM devices is still hindered by the dark current.In this paper,the 100×100 μm2 InGaAs-MSM photodetector is successfully fabricated.The dark current density is reduced to 0.6 pA/μm2(5 V)by designing InAlGaAs/InGaAs short period superlattices and InAlAs Schottky barrier enhancement and this improves the SNR.Parameters of the device are characterized as follows:the 3dB bandwidth is 6.8 GHz,the rise time is 58.8 ps,the responsibility is 0.55 A/W at 1550 nm and the external quantum efficiency of the absorption region is 88%.Inhibition mechanisms of the short period superlattices and Schottky barrier enhancement are analyzed.