Kee-Young Park

Improvement of Thermal Stability of Ni Germanide Using a Ni–Pt(1%) Alloy on Ge-on-Si Substrate for Nanoscale Ge MOSFETs

In this paper, thermally stable Ni germanide using a Ni-Pt(1%) alloy and TiN capping layer is proposed for high-performance Ge MOSFETs. The proposed Ni-Pt(1%) alloy structure exhibits low-temperature germanidation with a wide temperature window for rapid thermal processing. Moreover, sheet resistance is stable and the germanide interface shows less agglomeration despite high-temperature postgermanidation anneal up to 550 °C for 30 min. In addition, the surface of the Ni-Pt(1%) alloy structure is smoother than that of a pure Ni structure both before and after the postgermanidation anneal. Only the NiGe phase and no other phases such as PtxGey and NixPt1-xGey can be observed in X-ray diffraction results, but X-ray photoelectron spectroscopy shows that PtGe is formed during the postgermanidation anneal. The larger Pt atomic radius is believed to inhibit the diffusion of Ni into the Si substrate, thereby improving the thermal stability of the NiGe. The higher melting point of PtGe is also believed to improve thermal stability. Therefore, this proposed Ni-Pt(1%) alloy could be promising for high-mobility Ge MOSFET applications.

Ni Germanide Utilizing Ytterbium Interlayer for High-Performance Ge MOSFETs

In this article, ytterbium (Yb) incorporation into NiGe is proposed to improve the thermal stability of Ni germanide for high-performance Ge metal-oxide-semiconductor field-effect transistors (Ge MOSFETs). The Yb/Ni/TiN structure shows suppression of NiGe agglomeration and better surface morphology than the Ni/TiN structure after a postgermanidation annealing of up to 550°C for 30 min. It is notable that Yb atoms distribute uniformly at the top region of NiGe. NiGe agglomeration was retarded by Yb incorporation, and the thermal stability of NiGe was therefore improved.

Thermal Immune Ni Germanide for High Performance Ge MOSFETs on Ge -on- Si Substrate Utilizing

Highly thermally stable Ni germanide technology for high performance germanium metal-oxide-semiconductor field-effect transistors (Ge MOSFETs) is proposed, utilizing Pd incorporation into Ni germanide. The proposed Ni germanide shows not only the improvement of thermal stability but also the reduction of hole barrier height, which can improve the device on-current by reducing the Ni germanide to p+ source/drain contact resistance. The proposed Ni germanide showed a stable sheet resistance of up to 500degC 30-min postgermanidation annealing due to the suppression of agglomeration and oxidation of Ni germanide and the diffusion of Ni and Ge atoms by the incorporated Pd. Therefore, the proposed Ni0.95Pd0.05 alloy could be promising for the high mobility Ge MOSFET applications.

\hbox{Ni}_{0.95}\hbox{Pd}_{0.05}

In this article, thermally stable Ni germanide using palladium (Pd) incorporation is proposed for high performance germanium metal-oxide-semiconductor field-effect transistors, and a microstructural analysis of the Ni germanide is performed in depth. The proposed Pd/Ni/TiN structure exhibited a stable sheet resistance despite high temperature postgermanidation annealing of up to 500°C for 30 min. The cause of the improved thermal stability is determined to be caused by the pileup of Pd atoms at the bottom region of NiGe, which resulted in the retardation of NiGe agglomeration by the formation of PdGe or NiPdGe there.

Alloy

In this paper, barrier height between Ni-silicide and source/drain is reduced utilizing Pd stacked structure (Pd/Ni/TiN) for high performance PMOSFET. It is shown that the barrier height is decreased by Pd incorporation and is dependent on the Pd thickness. Therefore, Ni-silicide using the Pd stacked structure is promising for high performance nano-cale PMOSFET.

Microstructural Innovation of Ni Germanide on Ge-on-Si Substrate by Using Palladium Incorporation

The thermal stability of Ni germanide utilizing pure Ni and Ni-Pd alloy on Ge-on-Si substrate was studied. The proposed Ni-Pd alloy shows the highly thermal immune Ni germanide due to reduced oxidation and retarded Ni and Ge diffusion. Therefore, the Ni-Pd alloy could be promising for the high mobility Ge MOSFET applications.

Reduction of Barrier Height between Ni-silicide and p+ Source/drain for High Performance PMOSFET

In this study, thermal stability of Ni germanide on Ge-onSi substrate is improved using Ni-Pt(l%) alloy target. It is believed that Pt incorporation suppressed the oxidation of NiGe and Ni and Ge diffusion. The proposed Ni-Pt/TiN is also efficient in reducing hole barrier height between Ni germanide and source/drain, i.e., decrease of contact resistance therein. The extracted Schottky barrier height shows decrease of about 20 meV. Therefore, the proposed NiPt alloy could be promising for the high mobility Ge pMOSFET applications.

Thermal stability improvement of Ni germanide utilizing Ni-Pd alloy for nano-scale Ge MOSFETs

In this paper, the Ni-Co alloy was used for thermal stability estimation comparison with Ni structure. The proposed Ni/Ni-Co structure exhibited wider range of rapid thermal process windows, lower sheet resistance in spite of high temperature annealing up to for 30 min, more uniform interface via FE-SEM analysis, NiSi phase peak. Therefore, The proposed Ni/Ni-Co structure is highly promising for highly thermal immune Ni-silicide for nano-scale MOSFET technology.

Improvement of thermal stability and reduction of Schottky barrier height of Ni germanide utilizing Ni-Pt(1%) alloy on Ge-on-Si substrate

In this paper, Ni-Co alloy was used to improve thermal stability of Ni Germanide. It was found that uniform germanide is obtained on epitaxial Ge-on-Si substrate by employing Ni-Co alloy. Moreover, neither agglomeration nor penetration is observed during post-germanidation annealing process. The thermal stability of Ni germanide using Ni-Co alloy is improved due to the less agglomeration of Germanide. Therefore, the proposed Ni-Co alloy is promising for highly thermal immune Ni germanide for nano scale Ge-MOSFETs technology.