Morphological and phase stability of nickel–germanosilicide on Si1−xGex under thermal stress

Abstract

Continuous and uniform Ni͑Si,Ge͒ layers are formed on polycrystalline Si and Si 0.42 Ge 0.58 substrate films at 500°C by rapid thermal processing. The germanosilicide is identified as NiSi 0.42 Ge 0.58 , i.e., with the same Si-to-Ge ratio as in the substrate. The NiSi 0.42 Ge 0.58 layer has agglomerated at 600°C. This is accompanied by a diffusion of Ge out from the germanosilicide grains and the growth of a Ge-rich SiGe region in their close vicinity. These changes cause a slight variation in the atomic composition of Ni͑Si,Ge͒ detectable for individual grains by means of energy dispersive spectroscopy. Above 600°C, substantial outdiffusion of Ge from the Ni͑Si,Ge͒ grains occurs concurrently with the migration of the grains into the substrate film away from the surface area leaving a Ge-rich SiGe region behind. These observations can be understood with reference to calculated Ni-Si-Ge ternary phase diagrams with and without the inclusion of NiSi 2 . When Ge is present, the Ni-based self-aligned silicide process presents a robust technique with respect to device applications.

Schottky contact properties of Ni/n-poly-Si0.87Ge0.13/n-Si(100) heterostructure

“…And no phase of the Ni(SiGe) 2 type is observed. These findings are consistent with the results obtained by other researchers [16]. The diffraction intensity of SiGe (111) peak remains almost unchanged at 300 and 400 jC, and then decreases after annealing at higher temperatures.…”

Integrations and challenges of novel high-k gate stacks in advanced CMOS technology

“…FUSI gate integration is similar to the conventional CMOS process flow. And most FUSI gate electrode are known to have metal-like low resistivities (10-100 lX cm) [283][284][285][286][287][288][289][290][291]. It is also much easier to tune the work function as compared to other metallic gate electrodes [292], including different silicide phases, pre-doing of poly-silicon gate electrodes, controlling the FUSI gate compositions, and so on [247].…”

“…Nickel monosilicide (NiSi) is the desired low resistivity phase (11)(12)(13)(14)(15) lX cm), which is formed at temperature below 500°C allowing for a lower thermal budgets [315,316]. While at higher temperatures above 750°C, NiSi 2 with higher resistivity of $40 lX cm is formed [291], caused by silicon agglomeration. The temperature window for NiSi could be extended by introducing platinum to nickel or by implanting BF 2 [317,318].…”

Investigation of solid reaction between Fe and Si0.8Ge0.2

“…This suggests that the Ge atoms are expelled from the Fe(Si 1Àz Ge z ) grain boundary which enables them to react with the Si atoms to form Ge-rich-Si 1Ày Ge y surrounded by Fe(Si 1Àz Ge z ), where y40:2:Fe(Si 1Àz Ge z ). The phenomenon of separated Ge atoms is also found in Ge-Ni-Si and Ge-Co-Si systems [9,10]. In addition, the GIXRD spectrum shows that all the peaks are shifted toward larger 2y angles after annealing at temperatures up to 750 1C.…”