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

通过对Ge MOSFET有效迁移率和霍尔迁移率的比较，我们阐明了反型层载流子被捕获到位于导带和价带内的界面态，导致了有效迁移率的降低。此外，氢原子的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/Al_2O_3/Geox/Ge MOSFET的电子迁移率和空穴迁移率峰值分别为690和550 cm~2/V。还揭示了有效迁移率与表面取向的关系。此外，我们还展示了用Ge凝聚和Ge晶片键合方法制备的GOI小于20 nm的n-MOSFET和p-MOSFET，并对其迁移率进行了评价。

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.