Vacancy defects in germanium adversely impact the electrical performance of Ge based metal-oxide-semiconductor field-effect transistor in several ways. They behave as an acceptor site, thereby deactivating n-type dopants in the source/drain region. They could also increase substrate leakage currents and impact carrier lifetime in the channel region. Here, the electrical behaviour of vacancy defects in Ge was characterized and verified using spreading resistance profiling. The effect of thermal annealing upon the vacancy concentration was studied. Finally, passivation of these defects using F-ion implants was shown to demonstrate the feasibility of performance enhancement in Ge- metal-oxide-semiconductor field-effect transistors.

Fluorine Passivation of Vacancy Defects in Bulk Germanium for Ge Metal-Oxide-Semiconductor Field-Effect Transistor Application. W.S.Jung, J.H.Park, A.Nainani, D.Nam, K.C.Saraswat: Applied Physics Letters, 2012, 101[7], 072104