Nickel Silicide Formation using Pulsed Laser Annealing for nMOSFET Performance Improvement

Abstract

The formation of a uniform, high tensile stress and low silicide/Si interfacial resistance nickel silicide in nMOSFET by introducing pulsed laser annealing (PLA) is reported. This annealing approach facilitated the phase transformation of nickel silicide to Si-rich NiSi(x) compounds using a low-thermal-budget process, improves the silicide/Si interface regularity and avoids familiar (111) NiSi(2) facet formation at a laser energy of 1.5 J cm(-2). By increasing laser energy density up to 2.3 J cm(-2), the device performance and statistics junction leakage distribution were degraded due to the increased sheet resistance of silicide layer and the destroyed silicide/Si interface morphology. When the PLA with a laser energy density of 1.5 J cm(-2) was employed for nickel silicidation on the p-type Schottky diodes, a 0.16 eV hole Schottky barrier height (SBH) increase from 0.52 to 0.68 eV was observed. In addition, the application of PLA for source/drain silicidation of nMOSFETs demonstrated an 8% enhancement in I(on) I(off) characteristic relative to that obtained through the conventional two-step rapid thermal annealing (RTA). This PLA method holds promise as a potential replacement for current nickel silicide annealing approaches toward extremely scaled-down transistors. (C) 2011 The Electrochemical Society. [DOI: 10.1149/1.3601849] All rights reserved.