Tsukasa Itani

Low Temperature Synthesis of Plasma Teos SiO 2

In this study, we investigated the deposition temperatures affect on TEOS based Si0 2 properties and reaction mechanisms while changing the excitation frequency. We used a parallel-plate plasma reactor, and either 100 kHz or 13.56 MHz radio frequency to generate plasma. We found that 100 kHz plasma promotes SiO formation and improves the film properties at low deposition temperatures. We assume this to be due to the supplement of higher energy ions to the substrate surface in 100 kHz plasma. This in turn promotes the elimination reaction (condensation reaction) of OH that links to Si atoms as a terminator of surface SiO networks or precursor molecules.

Dependence of thermal stability of NiSi and Ni(Pt)Si /Si on crystal orientation

We report NiSi and Ni(Pt)Si films with excellent thermal stability showing a particular crystal orientation on Si(001). The Ni-silicide film with a deposition temperature of about 200 °C consists of a conformal domain structure. We examined detail crystallographic analysis of silicide and clarified the psudo-epitaxial growth of NiSi(202)//Si(220) [or NiSi(211)//Si(220)] was the key scheme of superior thermal stability. By using this optimized Ni-silicide formation process, we have fabricated Ni-silicide that is thermally stable up to 650 °C and shows low fluctuation in sheet resistance and low leakage current in electrical measurements. This process is a promising candidate for future silicidation technology.

Quasi Crystal Lindhard–Scharff–Schiott Theory and Database for Ion Implantation Profiles in Si1-xGex Substrate Based on the Theory

We propose an analytical model for ion implantation profiles in a Si1-xGex substrate with various content ratios x. The moments associated with the peak region were evaluated using the extended Lindhard–Scharff–Schiott (LSS) theory. The channeling length was related to the maximum range associated with electron stopping power only. We also express the shape of the channeling tail and the channeling dose empirically but with a universal form. We showed that the theory reproduces the experimental data well. Since the theory simultaneously gives information on the lateral distribution, we established a database of B, P, and As ion implantation profiles including their lateral distribution profiles in Si1-xGex substrates.