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Development of a "near-surface"-photodetector based on anomalous above-band-gap absorption band of SiGe

基于 SiGe 反常带隙上吸收带的“近表面”光电探测器的开发

基本信息

批准号：
12555085
负责人：
FUKATSU Susumu
金额：
$ 6.34万
依托单位：
The University of Tokyo
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2000
资助国家：
日本
起止时间：
2000 至 2002
项目状态：
已结题

项目摘要

Silicon-on-insulator (SOI) substrates have been in the focus of attention these days particularly from the perspective of developing high speed, less power-hungry electronics. The looming silicon-photonics on the other hand is to bring photonics/optoelectronics onto this otherwise purely electronic SOI chip. The problem then is that the conventional architecture of photonics/optoelectronics devices, at it stands, would not allow for a highly integrated circuit design, which can be traced back to the indirect band-gap of silicon that only weakly absorbs light thereby leaving a fairly large footprint.In this study, an attempt is made to create a new class of strongly-absorbing, on-chip quantum photodetector that takes advantage of an anomalous near-surface absorption band centered near 12eV developing in oxidized SiGe due to the relevant unique electronic states as opposed to those pertaining to the bulk. This above-band-gap absorption band was reproducible even in silicon-based systems short of Ge, which shows that it has to do with Si and hence its near-surface defects launched therein. A series of MSM (metal-semiconductor-metal) photodetecotrs prototypes with Schottky links was tested to examine such characteristics as spectral sensitivity in relation to wavelength selective detection, dynamic range of photoresponse, dark current, polarization-insensitiveness, and transient response including bandwidth reaching the subnanosecond domain. Interestingly, the absence of hole burning indicates that the 1.2eV band is not homogeneously broadened. Besides the issues that had been addressed in the original proposal, electroabsorption and electroreflectance were discovered during the course of this study, which holds considerable promise in building electro-optic modulator and tunable detector. The fabrication of an arrayed detector for mulitichannel spectroscopy and transparent fringe detection will remain as a subject of future study.

绝缘体上硅（SOI）衬底一直是人们关注的焦点，特别是从发展高速，低功耗电子产品的角度来看。另一方面，即将到来的硅光子学将把光子学/光电子学带到这个纯粹的电子SOI芯片上。那么问题是，光子学/光电子器件的传统架构，就目前而言，不允许高度集成的电路设计，这可以追溯到硅的间接带隙，其仅微弱地吸收光，从而留下相当大的足迹。片上量子光电探测器，其利用了在氧化SiGe中由于相关的独特电子态而产生的中心在12 eV附近的异常近表面吸收带，而不是与块体相关的电子态。即使在缺少Ge的硅基系统中，这种带隙以上的吸收带也是可再现的，这表明它与Si有关，因此其近表面缺陷在其中发射。一系列MSM（金属-半导体-金属）光电探测器的原型与肖特基链接进行了测试，以检查这样的特性，如光谱灵敏度的波长选择性检测，动态范围的光响应，暗电流，偏振不敏感性，瞬态响应，包括带宽达到亚纳秒域。有趣的是，没有烧孔表明1.2eV带不是均匀加宽的。除了在原方案中已经解决的问题外，在本研究过程中还发现了电吸收和电反射，这在构建电光调制器和可调谐探测器方面具有相当大的前景。多通道光谱和透明条纹探测的阵列探测器的制作仍将是未来的研究课题。