Xu Shengqiang, Han Kaizhen, Huang Yi-Chiau, Lee Kwang Hong, Kang Yuye, Masudy-Panah Saeid, Wu Ying, Lei Dian, Zhao Yunshan, Wang Hong, Tan Chuan Seng, Gong Xiao, Yeo Yee-Chia
Opt Express. 2019 Sep 16;27(19):26924-26939. doi: 10.1364/OE.27.026924.
High-performance GeSn multiple-quantum-well (MQW) photodiode is demonstrated on a 200 mm Ge-on-insulator (GeOI) photonics platform for the first time. Both GeSn MQW active layer stack and Ge layer (top Ge layer of GeOI after bonding) were grown using a single epitaxy step on a standard (001)-oriented Si substrate (donor wafer) using a reduced pressure chemical vapor deposition (RPCVD). Direct wafer bonding and layer transfer technique were then employed to transfer the GeSn MQW device layers and Ge layer to a 200 mm SiO-terminated Si handle substrate. The surface illuminated GeSn MQW photodiode realized on this platform exhibits an ultra-low leakage current density of 25 mA/cm at room temperature and an enhanced photo sensitivity at 2 μm of 30 mA/W as compared to a GeSn MQW photodiode on Si at 2 μm. The underlying GeOI platform enables monolithic integration of a complete suite of photonics devices operating at 2 μm band, including GeOI strip waveguides, grating couplers, micro-ring modulators, Mach-Zehnder interferometer modulators, etc. In addition, Ge CMOS circuits can also be realized on this common platform using a "photonic-first and electronic-last" processing approach. In this work, as prototype demonstration, both Ge p- and n-channel fin field-effect transistors (FinFETs) were realized on GeOI simultaneously with decent static electrical characteristics. Subthreshold swings of 150 and 99 mV/decade at |VD| = 0.1 V and drive currents of 91 and 10.3 μA/μm at |VG-VTH| = 1 V and |VD| = 0.75 V were achieved for p- and n-FinFETs, respectively. This works illustrates the potential of integrating GeSn (as photo detection material) on GeOI platform for Ge-based optoelectronics integrated circuits (OEICs) targeting communication applications at 2 μm band.
高性能锗锡多量子阱（MQW）光电二极管首次在200毫米绝缘体上锗（GeOI）光子学平台上得到展示。锗锡MQW有源层堆栈和锗层（键合后GeOI的顶部锗层）使用减压化学气相沉积（RPCVD）在标准（001）取向的硅衬底（施主晶圆）上通过单个外延步骤生长。然后采用直接晶圆键合和层转移技术将锗锡MQW器件层和锗层转移到200毫米二氧化硅终止的硅衬底上。在该平台上实现的表面照明锗锡MQW光电二极管在室温下表现出25 mA/cm的超低漏电流密度，与2μm波长下硅上的锗锡MQW光电二极管相比，在2μm波长处的光灵敏度提高到30 mA/W。底层的GeOI平台能够实现一整套工作在2μm波段的光子器件的单片集成，包括GeOI条形波导、光栅耦合器、微环调制器、马赫-曾德尔干涉仪调制器等。此外，还可以使用“光子优先、电子最后”的处理方法在这个通用平台上实现锗互补金属氧化物半导体（CMOS）电路。在这项工作中，作为原型演示，锗p沟道和n沟道鳍式场效应晶体管（FinFET）在GeOI上同时实现，具有良好的静态电学特性。对于p-FinFET和n-FinFET，在|VD| = 0.1 V时分别实现了150和99 mV/十倍频程的亚阈值摆幅，在|VG-VTH| = 1 V和|VD| = 0.75 V时分别实现了91和10.3 μA/μm的驱动电流。这项工作说明了在GeOI平台上集成锗锡（作为光探测材料）用于面向2μm波段通信应用的锗基光电子集成电路（OEIC）的潜力。
