Key Issues for the Development of a Ge CMOS Device in an Advanced IC Circuit

Passivation of the channel in the gate stack is the most important problem for introducing another material than silicon into the channel of CMOS devices. In order to compare the mobility values of different passivation techniques, we propose to use a parameter, which is a proportional to the drive current of the transistor. We call this parameter the channel mobility value and it is calculated from the transistor equation. This channel mobility value can be used to benchmark more consistently the different passivation techniques on germanium or other semiconductor materials. A second issue for CMOS scaling on Ge is the poor performance of nMOS devices and there seems no solution in sight for this problem. Therefore we promote the investigation of technologies to allow the introduction of III-V materials on Ge to make nMOS devices in III-V devices complementary with Ge pMOS. A third key issue is the development of a manufacturable and low defect density germanium-on-insulator (GeOI) technology on 200mm and larger substrate sizes.