Summary of Research Project Results under JSPS FY2001
"Research for the Future Program"

1.Research Institution The University of Tokyo
2. University-Industry Cooperative Research Committee
 153rd Committee on Plasma Materials Science
3.Term of Project FY 1997 〜 FY 2001
4.Project Number 97R15301
5.Title of Project Development of Ultra-high Rate Thermal Plasma Cluster Deposition Method for Well-controlled Nano-scopic Electronic Materials

6.Project Leader
Name Institution,Department Title of Position
Toyonobu Yoshida The University of Tokyo, Graduate School of Engineering Professor

7.Core Members

Names Institution,Department Title of Position
Kazuo Terashima The University of Tokyo, Graduate School of Frontier Sciences Associate Professor
Yuichi Ikuhara The University of Tokyo, Graduate School of Engineering Associate Professor

8.Summary of Research Results

The principal findings by the members of the team can be summarized as follows:

1. A ultra-clean thermal plasma deposition system was developed and was applied for the ultrafast deposition of Si films by injecting SiH4. The improvement of stability, controllability, and cleanliness of the process enabled the deposition of microcrystalline Si films at the ultrafast rate of over 1000 nm/s. Moreover, a minimum defect density of 7.2×1016cm-3 was achieved. Simulation and step coverage analysis suggested that the precursor is an approximately 1 nm cluster with a sticking probability of about 0.6.
2. A thermal plasma liquid-spray deposition system was developed. Using the system, epitaxial Li(NbxTa1-x)O3 films were successfully prepared on Al2O3(001) substrate with injecting the mixture of litium-niobium-tantalum alkoxide solutions. Deposition rates up to 0.5μm/min could be achieved. The film quality was found to be comparable with those deposited by other techniques.
3. We have developed a spatially high resolution chemical-structural analysis technique and high contrast imaging technique. The spatial resolution in chemical analysis was much improved for Energy Dispersive X-ray Spectroscopy, namely, probe current larger than 2nA could be obtained even in a probe diameter of 0.5nm. Moreover, the high resolution was clearly confirmed by direct observation of B and N atoms in a c-BN test specimen.
4. A joint system of external quadrupole static attraction ion trap (EQSIT) and quadrupole mass spectrometer or deposition stage has been constructed. When silane and decaborane gases were introduced, SixHy+ (x=1-4) and BMxHy+(x=1-20) ion clusters were observed. When number of boron atoms, x, is larger than 15, the nido-structure seems to be realized. On the other hand, the clusters with smaller x than 9 prefer fewer hydrogen atoms and may have more metallic bonding. Mixed ion cluster, B10SiHy+, was also produced by introducing the gas mixture.

9.Key Words

(1)Thermal plasma system、(2)Thermal plasma CVD、(3)Thermal plasma PVD
(4)Cluster deposition、(5)Ultra high rate deposition、(6)Microcrystalline Si film
(7)electro-optical oxide film、(8)Epitaxial growth、(9)nano-scale analysis