Oxidation of tantalum disilicide on polycrystalline silicon

Abstract

Articles you may be interested inEffects of tantalum penetration through hafnium oxide layer on carrier generation rate in silicon substrate and carrier mobility degradation Appl. Phys. Lett. 86, 012901 (2005); 10.1063/1.1845588Diffusion and oxidation of plasma-enhanced chemical-vapor-deposition silicon nitride and underlying metals Oxidation characteristics of the tantalum disilicide films have been investigated in the temperature range of 900°-1050 °C in dry oxygen and steam ambients. The silicide does not oxidize in dry oxygen and oxidizes in steam at a rate lower than that of doped polycrystalline silicon films as long as there is a polycrystalline silicon layer between the silicide and the gate oxide. Under these circumstances, the silicide retains its electrical and mechanical characteristics. The oxide on the silicide has an etch rate (in buffered hydrofluoric acid) similar to that of thermal Si0 2 on silicon. Electrical characteristics of the oxide appear to be similar to those ofthe wet oxide on polycrystalline silicon. In the absence of poly crystalline silicon, between the silicide and the gate oxide, oxidation leads to a loss in the conductivity of the silicide and eventually to a mechanical instability of the film. An oxidation mechanism, which assumes silicon diffusion by substitution through the silicide, has been proposed.PACS numbers: 68.90. + q, 81.60. -j, 68.55. + b, 8l.15.Cd

Characteristics of TaSi2 / Poly ‐ Si Films Oxidized in Steam for VLSI Applications

“…Calculated values of B and B/A are shown in Fig. A small decrease is noted in our data, while a strong decrease is observed from the results of Murarka et aL (4). In Fig.…”

“…4 and 5, respectively. It is plausible that small differences in the composition of the grown oxide, possibly resulting from the incorporation of tantalum, can be responsible for the factor-of-seven difference in the pre-exponential part of the parabolic rate constant observed between the data presented here and that presented elsewhere (4). 4, previously reported values of the parabolic rate constant from the oxidation of single crystal (111) and (100) silicon are shown (9), along with the results obtained in this study for TaSi2/poly-Si structures.…”

“…Several authors have already published overviews of TaSiJpoly-Si metallization schemes (1,2) and have shown that, by using TaSi2/poly-Si composite structures, low sheet resistance can be achieved while the advantages of silicongate properties and technology are maintained. In the case of steam oxidations (4), SiO2 was readily formed, and it was postulated that Ta and Si are both initially oxidized and produce a silicon-rich silicide at the silicide-SiO2 interface, thereby allowing silicon diffusion to occur and oxidation to continue (4). This was attributed to the presence of excess Ta at the silicide-SiO2 interface, which interfered with silicon diffusion by substitution on the TaSi2 lattice.…”

Tantalum and Tantalum Compounds

“…The tantalum -boron phase diagram [125] [126] are produced from the elements by heating in vacuo at 1000 -1500…”

Electrical and compositional properties of TaSi2 films

“…9 have reported their studies on TaSi 2 films formed on polysilicon by sintering tantalum thin films on doped polysilicon. al.…”