Operation of (111) Ge-on-Insulator n-Channel MOSFET Fabricated by Smart-Cut Technology

In this letter, we demonstrate the well-behaved operation of (111) Ge-on-insulator (GOI) n-channel metaloxide-semiconductor field-effect transistors (nMOSFETs) with excellent electrical characteristics. High crystal quality (111) GOI substrates for the fabrication of (111) GOI nMOSFETs were prepared by a smart-cut process combined with an annealing process at 550 °C. Excellent electrical properties of the (111) GOI substrates were achieved by using relatively low ion implantation (I/I) dose condition of 4 × 10
¹⁶
cm
^-2
. (111) GOI nMOSFETs were fabricated on these substrates, and the electrical characteristics were compared to those of the (100) GOI and (111) bulk ones. It is experimentally proved that the (111) GOI nMOSFET provides higher drive current and higher mobility than those of (100) GOI ones. In particular, the record high effective electron mobility of 943 cm
²
/Vs among reported GOI nMOSFETs is achieved for the present (111) GOI nMOSFETs.