Thermal Stability Of Ni Silicide Research Articles

Improvement of Thermal Stability of Nickel Silicide Using Co-Sputtering of Ni and Ti on Boron Cluster Implanted Ultra-Shallow Junction for Nanoscale CMOS Technology

In this paper, Ni-silicide formed by co-sputtering of Ni and Ti on a boron cluster (BF2, B18H22) implanted ultra-shallow source/drain for MOSFET (metal oxide semiconductor field effect transistor) is proposed. Ni and Ti with a TiN capping layer were deposited by co-sputtering on boron cluster implanted wafer. By analysis of its sheet resistance, interfacial structures, surface morphological stability, and phase formation after post-silicidation annealing, thermal stability of Ni-silicide was found to be improved a lot.

Improvement of Ni Silicide Thermal Stability By Using Vanadium Elements

Ni silicide thermal stability is improved by the use of a Ni-V (nickel vanadium) alloy target. The relationship between the formation temperature and the thermal stability of Ni silicide is investigated. The sheet resistance after the formation of Ni silicide with the Ni-V shows stable characteristics up to a rapid-thermal-process temperature of 700°C, while degradation of sheet resistance starts at that temperature in the case of pure-Ni. Moreover, the thermal stability improvement is demonstrated by the post-silicidation annealing. It is considered that the thermal robustness of Ni-V silicide is highly dependent on the formation temperature. With the increasing silicidation temperature (around 700°C), more thermally stable Ni silicide is formed in comparison to the low-temperature case using the Ni-V. A Ni-V alloy target is utilized to form Ni silicide. The V and the V-trap complexes are explained to block the transformation from NiSi to NiSi2 so as to improve the Ni silicide thermal stability.

Effects of B or Al Interface Layers on Thermal Stability of Ni Silicide on Si

A new method is proposed to address the degradation of thermal stability in Ni silicide on heavily doped N-type Si substrates. Layered deposition of Al or B at the Ni/Si interface prior to silicidation was found to improve the thermal stability of Ni silicide, as evaluated by the sheet resistance vs. silicidation temperature properties. The improvement is attributed to suppression of the agglomeration of silicide layers. An Al layer was effective only when it was located at the Ni/Si interface prior to the silicidation process. The use of a B layer was preferable to that of Al when considering lower junction leakage.

Improvement of thermal stability of Ni silicide on N +–Si by direct deposition of group III element (Al, B) thin film at Ni/Si interface

The direct deposition of a thin Al or B layer at Ni/Si interface was proposed as a new method to solve a problem of degraded thermal stability of Ni silicide on heavily doped N +–Si substrates. Significant improvement of thermal stability evaluated by the sheet resistance vs. silicidation temperature properties was observed. The improvement is attributed to suppression of agglomeration of the silicide layers. The Al layer was effective only when it was located at the Ni/Si interface before the silicidation process. The deposited Al and B layers under Ni layer segregated at the surface after the silicidation process. The use of B layer was preferable to control the phase transition from NiSi to NiSi 2.

Improvement of Thermal Stability of Ni Silcide by Additive Metals with Specific Introduction Processes

A new processe to improve thermal stability of Ni silicide, so called PSMD (post silicidation metal doping) in which additive metals were introduced to pre-formed NiSi was proposed. In situ deposition of thin Hf or Pt layer on the NiSi layer resulted in improvement of thermal stability evaluated by sheet resistance and morphology in the following RTA process at higher temperatures.

AEM Study on the Phase Transformation of Nickel Silicides in the Ni<sub>1-x</sub>Ta<sub>x</sub>/Si System

We investigated the phase transformation and thermal stability of Ni silicides formed in Ni/Si and Ni0.95Ta0.05/Si systems. The sheet resistance values of the silicide in the Ni0.95Ta0.05/Si system were lower than those in Ni/Si system at any temperature. The enhancement of thermal stability is closely related to the phase transformation occurred during post heat-treatment. Microstructure of the phases formed by reaction was investigated by analytical electron microscopy (AEM) and the phase identification of Ni silicide was carried out using convergent beam electron diffraction (CBED) technique. It was found that a Ta rich layer formed on the top of the Ni silicide layer and small amount of Ta dissolved into the silicide layer. By addition of Ta atoms, phase transformation from NiSi to NiSi2 is retarded and thermal stability of Ni silicide is improved.

나노급 CMOSFET을 위한 Boron Cluster(B18H22)가 이온 주입된(SOI 및 Bulk)기판에 Ni-V합금을 이용한 Ni-silicide의 열안정성 개선

In this paper, the formation and thermal stability characteristics of Ni silicide using Ni-V alloy on Boron cluster (<TEX>$B_{18}H_{22}$</TEX>) implanted bulk and SOI substrate were examined in comparison with pure Ni for nano-scale CMOSFET. The Ni silicide using Ni-V alloy on <TEX>$B_{18}H_{22}$</TEX> implanted SOI substrate after high temperature post-silicidation annealing showed the lower sheet resistance, no agglomeration interface image and lower surface roughness than that using pure Ni. The thermal stability of Ni silicide was improved by using Ni-V alloy on <TEX>$B_{18}H_{22}$</TEX> implanted SOI substrate.

Improvement of Thermal Stability of Nickel Silicide Using Multi-Capping Structure

In this paper, the electrical properties of NiSi have been characterized using multi capping layer structure for nano CMOS application. We have investigated the formation and thermal stability of Ni silicide using Ni, Ti and TiN capping layers (Ti/Ni/TiN) as a function of Rapid Thermal Processing (RTP) temperature. It was shown that the NiSi with multi capping layer has lower sheet resistances than that with single capping (TiN) layer. NiSi with multi capping layer also showed much better thermal stability. It was verified that the formation Ni-Ti-Si ternary like layer at the top region of thhe NiSi results in improvement of thermal stability.

Study of thermal stability of nickel silicide by X-ray reflectivity

The thermal stability of Ni silicide, in comparison to the more conventionally used Co silicide, is studied by X-ray reflectivity. These data were complemented by sheet resistance measurements, transmission electron microscopy, time-of-flight Rutherford backscattering spectrometry, X-ray diffraction and time-of-flight elastic recoil detection analysis.

Improved thermal stability of Ni silicide on Si (100) through reactive deposition of Ni

The effect of reactive deposition of Ni on the thermal stability of Ni silicide has been investigated in this study. In the case of room-temperature-deposited Ni, the agglomeration of Ni silicide, which induced the thermal instability during subsequent annealing, started to appear at 600 °C and the sheet resistance was increased abruptly after high-temperature anneals. However, when the Ni was deposited on the heated Si substrate (reactive deposition of Ni), the sheet resistance of Ni silicide film exhibited a constant value of about 7.91 Ω/□ at the whole reaction temperature, especially at 900 °C.

Improvements in Both Thermal Stability of Ni-Silicide and Electrical Reliability of Gate Oxides Using a Stacked Polysilicon Gate Structure

A process design is presented for improving the thermal stability of Ni-silicide (nickel-silicide) using a stacked polysilicon gate structure. The Ni-silicide formed has low sheet resistance up to 800°C on a silicidation process. Additionally, the metal-oxide-semiconductor (MOS) capacitors fabricated using these proposed gate structures demonstrate higher electrical reliability for gate oxides than those of nonstacked films. That is, the gate oxides of the MOS capacitors were only slightly degraded after silicidation step at 800°C. In conclusion, the Ni-silicide formed on those stacked polysilicon gates are attractive in fabricating ultralarge scale integration (ULSI) circuits because both the thermal stability of Ni-silicide and the reliability of gate oxides are improved simultaneously. © 2001 The Electrochemical Society. All rights reserved.