Ge/SiGe异质结构肖特基源漏MOSFET

Schottky Barrier S /D Metal Oxide Semiconductor Field Effect Transistors with Ge /SiGe Heterostructure

制备了氧化铪(HfO2)高k介质栅Si基Ge/SiGe异质结构肖特基源漏场效应晶体管(SB-MOSFET)器件,研究了n型掺杂Si0.16Ge0.84层对器件特性的影响,分析了n型掺杂SiGe层降低器件关态电流的机理。使用UHV CVD沉积系统,采用低温Ge缓冲层技术进行了材料生长,首先在Si衬底上外延Ge缓冲层,随后生长32 nm Si0.16Ge0.84和12 nm Ge,并生长1 nm Si作为钝化层。使用原子力显微镜和X射线衍射对材料形貌和晶体质量进行表征,在源漏区沉积Ni薄膜并退火形成NiGe/Ge肖特基结,制备的p型沟道肖特基源漏MOSFET,其未掺杂Ge/SiGe异质结构MOSFET器件的空穴有效迁移率比相同工艺条件制备的硅器件的高1.5倍,比传统硅器件空穴有效迁移率提高了80%,掺杂器件的空穴有效迁移率与传统硅器件的相当。

Si-based Ge/SiGe heterostructure Schottky barrier source and drain metal oxide semiconductor field effect transistors （SB-MOSFETs） with hafnium dioxide high-k gate were fabricated. The effect of the n-type doped Si0.16Ge0.84 layer on the device performance was investigated, and the mechanism of the device off-state current reduction caused by the n type doping SiGe layer was analyzed. Firstly, Ge buffer was fabricated with low-temperature Ge buffer technique. Then a 32 nm Si0.16Ge0.84 layer and a 12 nm Ge layer were grown on the Ge buffer in the same UHVCVD system. For comparative study, the 32 nm Si0.16Ge0.84 layer was controlled undoped or n-type doped by P. For all samples, 1 nm Si layer was grown to passivate the Ge surface. Atomic force microscopy and X-ray diffraction were used to characterize the surface morphology and crystal quality of the materials. NiGe/Ge Schottky junctions in source and drain were formed by nickel layer deposition and anneal. The fabricated Ge/SiGe heterosturctual MOSFET device without n-type doping shows 150% enhancement of the hole effective mobility over that of the control Si device and about 80% enhancement over the universal Si device. And the device with n-type doping shows a comparable hole effective mobility with the universal Si MOSFET device.