用于远红外探测的Si:P阻挡杂质带红外探测器研制

Si: P blocked impurity band detectors for far infrared detection

提出了全外延技术方案制备阻挡杂质带薄膜,避免了离子注入制备背电极层影响外延薄膜质量的技术难点.基于硅器件工艺设计制作了Si：P阻挡杂质带红外探测器.测量了器件的光电流响应谱和暗电流特性曲线,指认了叠加在光电流响应谱上的尖锐杂质峰对应阻挡层中磷原子的杂质跃迁.研究了器件在低温下小偏压范围内的暗电流起源.通过对计算结果分析,排除了该区域暗电流起源于热激发电导和跳跃式电导的可能,指出暗电流来自器件对冷屏的光电响应.器件工作温度5 K,工作偏压1.6 V时,响应波段覆盖2.5-40μm,峰值波长28.8μm,峰值响应率20.1 A/W,峰值探测率3.7×10^13cm·Hz1/2/W（背景光子通量低于1013ph/cm^2·s）.

Blocked impurity band detectors are of interest for various astronomy applications such as the Infrared Astronomical Satellite and Cosmic Background Explorer. The fabrication details and characterization of Si： P blocked impurity band detectors have been reported. The bottom contact was epitaxially grown instead of utilizing ion-implantation to improve the quality of epitaxial stack. The photocurrent spectra and dark current of the detectors have been measured. The spectral response extends from 2. 5μm to 40 μm. Several additional sharp peaks superimposed on the broadband response are designated to associate with impurity transitions of phosphorus in the blocking layer. The origin of dark current at small bias has been studied at lowtemperature. It was found that the shield of cryostat is the source of the background infrared light which hits the detectors to produced the dominant dark current at this regime. The detectors attain a peak responsivity of 20. 1 A / W（ at 28. 8） and peak detectivity of 3. 7 ×10^13cm·Hz1 /2/ W（ belowa flux of 1013 ph / cm^2·s）,which exhibits highly competitive figure of merits.