Opportunities of high performance Ge CMOS

摘要

Ge is not a new material but now spotlighted for beyond Si-scaled CMOS. Ge p-MOSFETs have been well investigated and its high performance has so far been demonstrated. On the contrary, an achievement of high electron mobility Ge n-MOSFETs is quite challenging due to a large amount of interface states near the conduction band edge. So, we first discuss how to overcome "intrinsic challenges in Ge n-MOSFETs" from thermodynamic viewpoint of GeO_2 on Ge. A very low D_(it) (＜10~(11) eV~(-1)cm~(-2)) at Ge/GeO_2 interface and a very high peak electron mobility in Ge n-MOSFETs are presented. This is further extended to scaled gate stacks on Ge by controlling the oxygen potential of dielectric films on Ge.