Interfacial reactions of Ni on Si1−xGex (x=0.2, 0.3) at low temperature by rapid thermal annealing

Abstract

The interfacial reaction of Ni with relaxed Si 1Ϫx Ge x ͑xϭ0.2,0.3͒ films in the low temperature range, viz., 300-500°C, has been investigated and compared with that of Ni with Si ͑i.e., xϭ0͒. Ni 2 (Si 1Ϫx Ge x ͒ and Ni 3 (Si 1Ϫx Ge x ) 2 were observed at 300°C whereas a uniform film of Ni͑Si 1Ϫx Ge x ͒ was formed at 400°C for both Si 0.8 Ge 0.2 and Si 0.7 Ge 0.3 substrates. At 500°C, a mixed layer consisting of Ni(Si 1Ϫy Ge y ) and Si 1Ϫz Ge z was formed with a relation of zϾxϾy. Sheet resistance measurement results show that the silicided film attains its lowest value at an annealing temperature of 400°C. The approximate values of the resistivity of the corresponding uniform Ni(Si 1Ϫx Ge x ) (xϭ0.2, 0.3) derived from the transmission electron microscope and sheet resistance results are 19 and 23 ⍀ cm, respectively.

Formation of ternary Ni-silicide on relaxed and strained SiGe layers

“…It has to be considered that the silicidation process may be affected by the strain in the top Si layer which depends on the Ge content and the degree of strain relaxation of the SiGe layer. Among the silicides used for MOS devices, Ni-silicide appears to be the most attractive material for the metallization of the strained layer system due to its low resistivity, high scalability, and the essential capability to form low resistivity Ni-germanosilicide at low temperatures [4,5]. In this study we investigated the formation and microstructure of ternary Ni-silicides on SiGe layers with different compositions and with different relaxation degrees.…”

Impact of an ultra-thin Ti interlayer on the formation of NiSiGe/SiGe

“…Based on our RBS data and simulation, it is calculated that the Ge concentration of Ni(Ti)SiGe layer is lower than NiSiGe layer w/o Ti incorporation. Zhao et al reported that the higher Ge content SiGe reacts with Ni, the lower thermal stability of NiSiGe shows [5]. Thus, low Ge concentration in Ni(Ti)SiGe layer contributes to the high thermal stability.…”

“…The difficulty of the Ni/SiGe system to form a highly uniform layer is due to the different absolute enthalpy of formation between NiSi (À45 kJ mol À1 ) and NiGe (À32 kJ mol À1 ) [4]. Ge out-diffusion has been shown to be the dominant mechanism, leading to agglomeration of Ni-germanosilicides (NiSiGe) [5]. On the other hand, SiGe alloys are already employed in the source/drain (S/D) or channel areas of pMOSFETs in order to increase the hole mobility [6,7].…”

Ni-Containing Electrodes for Compact Integration of Resistive Random Access Memory With CMOS

“…It can be also seen that the XRD spectra of Ni(Ge 1−x Si x ) films are quite similar to those of NiSi, suggesting that Ge did not change the bulk properties of the silicide. Therefore, the difference of R S among the films is believed to be due to the different amount of SiGe grains present in the silicide films [9]. In addition, x in two Ni(Ge 1−x Si X ) films was verified by X-ray photoelectron spectroscopy (XPS) to be around 0.…”