Understanding of carrier transport mechanism in Ge MOS interfaces and establishment of mobility enhancement technologies

通过对Ge mosfet的有效迁移率和霍尔迁移率的比较，我们已经明确了反转层载流子被困在位于导价带内的界面态中，导致有效迁移率降低。原子氘退火有利于降低界面态，提高有效迁移率。ECR等离子体氧化制备的EOT为0.76 nm的HfO2/Al2O3/GeOx/Ge mosfet的峰值电子迁移率和空穴迁移率分别为690和550 cm2/Vs。同时还揭示了有效迁移率与表面取向的关系。此外，我们还通过Ge缩合和Ge晶圆键合制备了厚度小于20 nm的GOI n-和p- mosfet，并对其迁移行为进行了评价。

We have clarified from comparison between effective and Hall mobility of Ge MOSFETs that inversion-layer carriers are trapped into interface states locating inside the conduction and valence bands, leading to the reduction in the effective mobility. Also, atomic deuterium annealing is fond to reduce the interface states and to increase the effective mobility. Also, HfO2/Al2O3/GeOx/Ge MOSFETs with EOT of 0.76 nm, realized by ECR plasma oxidation, exhibited peak electron and hole mobility of 690 and 550 cm2/Vs, respectively. The surface orientation dependence of the effective mobility has also been revealed. In addition, we demonstrated GOI n- and p-MOSFETs with GOI thinner than 20 nm, fabricated by the Ge condensation and Ge wafer bonding, and evaluated the mobility behaviors.