Enhancement of thermal stability of NiSi films on (100)Si and (111)Si by Pt addition

Abstract

The effect of a small amount of Pt (5 at. %) on the thermal stability of NiSi film on (100) and (111) Si substrates has been investigated both by in situ annealing inside an x-ray photoelectron spectroscopy system and by ex situ rapid thermal annealing. The addition of platinum increases the disilicide nucleation temperature to 900 °C leading to a better stability of NiSi at high temperatures. In the presence of Pt, NiSi films on both (111)Si and (100)Si substrates develop a texture with the relationship (100)NiSi∥(111)Si and (010)NiSi∥(100)Si. The increase in thermal stability has been explained in terms of the nucleation concept.

Three-Dimensional Atom-Probe Tomographic Studies of Nickel Monosilicide/Silicon Interfaces on a Subnanometer Scale

“…The presence of high-diffusivity GB paths makes it easier for Pt to diffuse to the nickel monosilicide/Si interface even for short annealing times. This may be responsible for the ECS Transactions, 19 (1) 303-314 (2009) reported modification of the texture of NiSi thin-films with Pt additions [9,11,[27][28][29]. In light of the discovery of Pt short-circuit diffusion along GBs, the observed modification of the NiSi grain size [30] and morphology may be explained by solute drag [31] on GBs due to Pt.…”

Texture in thin film silicides and germanides: A review

“…19 As the miscibility of PtSi in NiSi is high due to the similar orthorhombic MnP-type structure of the NiSi lattice and the PtSi lattice, the alloyed Pt gets easily incorporated into the NiSi and a Ni 1Àx Pt x Si layer is formed. The influence of these small concentrations of Pt on the texture of the resulting Ni 1Àx Pt x Si film compared to a pristine NiSi layer was investigated in 2004 by Detavernier et al using synchrotron based pole figure measurements.…”

“…% of Pt to the nickel layer results in an improved morphological stability. 118 Furthermore, the addition of Pt has the added advantage that the phase stability of NiSi is also improved (by shifting the nucleation of NiSi 2 to higher temperatures), 19 thus tackling the second degradation mechanism. Details on how the addition of alloying elements can influence the texture and hence the morphological stability of NiSi (and other silicide) films will be discussed in Section V C.…”

“…18 In modern planar CMOS technology, NiSi modified by the addition of a small amount of Pt still is the contacting material of choice. 19 For new device architectures such as finFETs, which allow for a further size-reduction, the criteria for contacting materials have changed drastically. These new criteria together with the availability of fast anneals have allowed the contacts to evolve back towards silicides that can withstand higher thermal budgets.…”

Work function modulation of PtSi by alloying with Yb

“…Therefore, the SBH modulation of the contact material has been widely studied [3,4,5]. Mono-silicide, such as NiSi is expected to be a candidate for the contact material with shallow junction, however, its poor thermal stability and difficulty to form thin NiSi layer is reported [6,7]. PtSi is a promissing contact material for PMOS source and drain, because of its excellent thermal stability, low Si consumption and low SBH for hole.…”