Analysis of the relationship between the kink effect and the indium levels in MOS transistors

In this work, we investigate the effects of indium ion implantation on the channel of nMOSFETs. Deep level transient spectroscopy (DLTS) and admittance spectroscopy (AS) measurements have been made on a series of indium doped silicon N+P structures and MOS capacitors. To analyse the indium-related levels in nMOSFETs, we used a low frequency (LF) output conductance dispersion analysis, which is based on the Gain-Phase versus frequency at different temperatures. These experiences show that the indium level when operated at low temperatures at which the majority of carriers freeze-out exhibit a kink effect. The effects of indium doping on the kink were studied using the variation of channel conductance gd and transconductance gm versus temperature in the kink zone. The excess drain current versus drain and gate voltage show the maximums of both conductance gd and transconductance gm at around T = 124 K when the indium level is activated.