AFM/SCM及LBIC技术在平面型保护环结构InGaAs探测器设计中的应用(英文)

OPTIMUM GUARD-RING FOR PLANAR InP/InGaAs PHOTODIODE:CHARACTERIZED WITH AFM,SCM and LBIC

为研究保护环结构对平面型正照射式InP/InGaAs探测器光敏元扩大现象的抑制作用,设计并研制了带有不同保护环-光敏元间距的InGaAs探测器.通过原子力显微镜（AFM）及扫描电容显微镜（SCM）获得了保护环与光敏元之间的实际距离.利用激光束诱导电流（LBIC）技术研究了带有保护环结构的InGaAs探测器的光响应特性.研究表明,无保护环结构的探测器的LBIC信号可以用指数衰减函数描述,而带有保护环结构的探测器的LBIC信号则遵从高斯分布.引入保护环结构后,器件光敏元的扩大量会随着保护环-光敏元间距的减小而线性减小.在器件设计中,比较合适的保护环-光敏元间距应介于7~12μm之间.

To study the guard-ring suppression effect on the extension of the photo-sensitive area in planar-type front illuminated InP/InGaAs hetero-structure detector,the InGaAs photo detectors with different distances between guard-ring and PN junction were designed and fabricated.The actual distance between guard-ring and PN junction of the detector was calculated based on the atomic force microscopy（AFM） and scanning capacitance microscopy（SCM） measurements.The characteristics of the photo response of the detectors with guard-ring were carried out with laser beam induced current（LBIC） method.It was indicated that LBIC signal of the photo detector without guard-ring fit well with the exponential decay function,while that of detector with guard-ring followed the Gaussian distribution.The extension value of the photo-sensitive area decreased linearly as the distance between the guard-ring and PN junction decreased.It was concluded that the appropriate gap between the guard-ring and PN junction should be in the range of 7 to 12μm.