基于应变锗的金属—半导体—金属光电探测器

Metal-Semiconductor-Metal Photodetectors Based on Strained Germanium

通过对锗(Ge)半导体材料进行拉伸应变和n型掺杂,可以提高其电子迁移率和发光性能。将薄膜卷曲技术与微电子加工技术相结合,制备出悬浮的Ge微米带结构,实现了单轴和双轴2种不同的应变状态,并且可以通过调整光刻图案来控制Ge的应变状态和大小。利用这一方法,制备出了高性能双轴应变Ge对称型肖特基接触金属-半导体-金属(MSM)光电探测器。经测试,在1 V偏压和入射功率为1 000 nW的863 nm激光下,该探测器具有低至nA量级的暗电流和高达713的电流开/关比。该性能的实现主要是依赖于双轴应变和掺杂对Ge能带的修饰。研究结果展示了应变Ge在光电探测领域的优势,也证明了其在Si兼容光学通信设备中的应用潜力。

The electron mobility and luminescent properties of germanium(Ge) semiconductor materials can be improved by tensile strain and n-type doping.By combining the thin film crimping technology with microelectronic processing technology,a suspended Ge micron band structure was prepared,which realized two different strain states of uniaxial and biaxial axis.The strain state and value of Ge can be controlled by adjusting the lithography pattern.A high performance biaxial strained Ge symmetric Schottky contact metal-semiconductor-metal(MSM) photodetector was fabricated using the technique.At a bias voltage of 1 V and incident 863 nm laser power of 1 000 nW,the detector has a dark current as low as nA level and an on/off current ratio up to 713.The realization of the performance mainly depends on biaxial strain and doping modification of Ge energy band.The study results show the advantages of strained Ge in the field of photoelectric detection,and also prove its application potential in silicon-compatible optical communication equipment.