MATSUMURA Laboratory
<Major Research Areas>Thin film deposition, Semiconductor device engineering, Electronic material engineering

Development of the novel thin film formation method and its application to semiconductor device manufacturing processes

Research activity

　　We have been investigating catalytic chemical vapor deposition (Cat-CVD) method and its industrial application, by which devicequality thin films can be deposited at low temperature below 300˚C without using plasma. Unlike conventional low temperature plasma-enhanced CVD (PECVD), material gases are decomposed on heated catalyzer surface and the cracked gas molecules move onto substrates to form thin films, resulting in no plasma damage to substrates. Furthermore, Cat-CVD method has high efficiency of gas use compared with PECVD because of the higher collision probability of gas molecules with 2-dimensional catalyzer surface than that with high-energy electrons distributed in 3-dimensional space in case of PECVD. Since deposition area can be easily enlarged by expanding catalyzer installation area, Cat-CVD method is expected to be utilized as industrial technology to fabricate large-scale thin-film devices such as thin-film solar cells and thin-film transistors (TFTs) for pixel-controlling devices of liquid crystal displays (LCDs) and organic light-emitting diodes (OLEDs). Furthermore, many kinds of high-quality thin films utilized for semiconductor integrated circuit (IC) can be formed by Cat-CVD method.
　　Recently, low-temperature deposition of silicon nitride (SiN x) films around room temperature has been established in Cat-CVD method, so that we have been investigating application of SiN x films to gas barrier structures for organic films and OLEDs. Organic films such as PTFE can also be formed by Cat-CVD method using proper material gases and catalyzers. Moreover, since the radical density generated by Cat-CVD method is one or two orders of magnitude higher than that in PECVD, new applications of Cat-CVD technology to high-density radical generator, photo-resist removal, surface treatment, and postannealing process have been developed. This technology can be applied to etching and chamber cleaning using halogen gases, so that consistent process of film deposition, etching, and chamber cleaning can be established.
　　In our laboratory, we have been investigating application of Cat-CVD processes for various devices and prerequisite technologies for mass-productive Cat-CVD equipment. Cat-CVD method has become worldwide technology and international conference on Cat-CVD process has been established. We have been playing a central role in this research field.

Equipment

Cat-CVD equipment for integrated circuit, Cat-CVD equipment for barrier film formation for organic materials, Cat-CVD equipment for solar cells, Cat-CVD equipment for fundamental investigation of reaction of catalyzers to material gases, Cat-CVD equipment for organic film formation

The main research achievements in the past five years

1. H. Matsumura, M. Miyamoto, K. Koyama, and K. Ohdaira,Drastic Reduction in Surface Recombination Velocity of Crystalline Silicon by Surface Treatment Using Catalytically-Generated Radicals,Sol. Energy Mater. Sol. Cells, 95, 797-799 (2011).
2. K. Koyama, K. Ohdaira, and H. Matsumura,Extremely low surface recombination velocities on crystalline silicon wafers realized by catalytic chemical vapor deposited SiNx/a-Si stacked passivation layers,Appl. Phys. Lett., 97, 082108, (2010).
3. K. Ohdaira, T. Nishikawa, and H. Matsumura, Variation of Crystallization Mechanisms in Flash-Lamp-Irradiated Amorphous Silicon Films, J. Cryst. Growth, 312, 2834-2839 (2010).
4. N. T. T. Kieu, K. Ohdaira, T. Shimoda, and H. Matsumura,A Novel Technique for Formation of Metal Lines by Functional Liquid Containing Metal Nano-Particles and Reduction of Their Resistivity by Hydrogen Treatment,J. Vac. Sci. Technol. B, 28, 775-778 (2010).
5. H. Matsumura, K. Ohdaira, and S. Nishizaki,Advantage of Plasma-Less Deposition; Cat-CVD Fabrication of a-Si TFT with Current Drivability Equivalent to Poly-Si TFT,Physica Status Solidi C, 7, 1132-1135 (2010).