Gate induced floating body effects in TiN/SiON and TiN/HfO2 gate stack triple gate SOI nFinFETs

Abstract: In this paper, the appearance of gate induced floating body effects in triple gate SOI nFinFETs with TiN/SiON and TiN/HfO2 gate stacks is investigated. Different floating body effects (FBEs) are found to appear under moderate accumulation back gate bias (V BG) conditions in devices with wide and long enough geometries. In particular, a second peak in the linear transconductance (g mf), associated with electron valence band (EVB) direct tunneling, is observed in TiN/SiON devices for front gate voltages (V FG) around 0.8V. Interestingly, in spite of showing about two orders of magnitude lower total gate current, a second peak in g mf is also found in TiN/HfO2 devices for V FG around 1.1V. Under the accumulation V BG conditions in which FBEs are observed, front gate switch drain current (I D) transients are also appreciated. Interestingly, a change in the shape of I D transients is observed for V FG conditions in which EVB majority carriers are injected into the floating fin. The I D transients, as well as the second peak of g mf and other FBEs, are found to gradually diminish for strong accumulation V BG conditions or reduced geometry dimensions. [Copyright &y& Elsevier]