Application of Flash Lamp Annealing for Controlled Nickel Silicidation of Silicon Nanowires

Silicon (Si) nanowires (NWs) have potential applications in various areas including electronics, opto-electronics and biochemical sensing. These wires are used to fabricate electronic devices with new architectures to complement the scaling down of electronic circuits. Our work focuses on one such architecture called Reconfigurable field effect transistors (RFET). An RFET is a Nickel(Ni)Si2-Si-NiSi2 Schottky junctions based device, which has an intrinsic Si channel. To fabricate an RFET, SiNWs are silicided at both ends to form Schottky junctions with the Si channel. Typically, it has two gates placed on each of the two Schottky junctions. It can be tuned to p- or n- polarity by applying appropriate electrostatic potential at one of the gates. Therefore, functional complexity and performance of electronic circuits can be enhanced using such FETs. Formation of NiSi2 is a pre-requisite for proper operation of these devices because metal work function of NiSi2 aligns itself near the mid-bandgap of Si. This enables band bending by application of an appropriate electrostatic potential for the operation of devices either as p- or as n- FET. We report our results on Ni silicidation using flash lamp annealing. By optimizing the silicidation process, control over the diffusion of Ni into the nanowire and proper silicide phase formation is achieved.