Japanese MOCVD Equipment Manufacturer Koh Matsumoto: GaN-on-Si is Definitely One of the Technologies for LED's Future Development

Recently, competition in the MOCVD market for LED equipment has been intense. Besides the industry's two leading manufacturers, German company Aixtron and American company Veeco, there is actually a stage for other equipment manufacturers. Taiyo Nippon Sanso Corporation (TAIYO NIPPON SANSO) was established in 1910 and is the largest industrial gas and air separation equipment manufacturer in Japan, ranking among the top five in the global industrial gas industry. Looking at Metal-Organic Chemical Vapor Deposition (MOCVD) equipment, the top three MOCVD manufacturers globally are German company Aixtron, American company Veeco, and Japanese company Taiyo Nippon Sanso. In 2011, these three companies had a combined global market share of 98.4%. Among them, although Taiyo Nippon Sanso's global market share is far lower than Aixtron and Veeco, at only 5.9%, its domestic market share in Japan is as high as 70%-80%, making it the largest MOCVD manufacturer in Japan.

In addition to inviting Dr. Koh Matsumoto, Chairman of Taiyo Nippon Sanso (Representative Director and President Matsumoto Koh), to share insights on LED equipment technology improvements and the current status and trends of the LED industry, our reporter also conducted an exclusive interview with him, asking him to provide valuable industry experience. Dr. Matsumoto Koh specializes in research on photosensitive processes for ETL, is dedicated to designing and producing MOVPE tools, and is also engaged in research on CS epitaxial growth and reactor development.

Dr. Koh Matsumoto (Matsumoto Koh), Representative Director and President of Taiyo Nippon Sanso Corporation, gave a speech at Taipei LEDforum 2011 titled "Using Innovative MOCVD Tools: Gallium Nitride on Sapphire and Silicon Substrates to Increase LED Production Capacity."

　　LED Production Technology Advancement: Evolution of Sapphire Substrate Sizes

　　President Matsumoto Isao pointed out that currently Taiwanese and Japanese manufacturers mostly use 4-inch sapphire substrates for LED applications, while manufacturers in mainland China primarily use 2-inch sapphire substrates. With the continuous improvement of equipment efficiency and LED technical expertise, it is estimated that next year, 4-inch sapphire substrates will also receive widespread attention from LED manufacturers. Although 6-inch sapphire substrates are still limited by current technology, resulting in LED chip production yield and breakage rates that remain bottlenecks to be overcome.

　　Taiyo Nippon Sanso will announce its latest MOVPE equipment UR26K in 2012. For 6-inch substrates, a single production run will increase from the original output of 6 wafers to 10 wafers, not only multiplying the number of chips per wafer, but also significantly reducing costs. Through the composition of the gallium nitride structure, the number of stacked multiple quantum wells can be successfully reduced, and the single operation time is also significantly shortened, with daily output greatly increased by approximately double.

　　With continuous improvements in equipment technology, Dr. Matsumoto Isao believes that MOVPE production capacity doubles approximately every four years. In addition, he believes that GaN-on-Si is certainly one of the technologies for future development. However, due to current technical difficulties — since the thermal expansion coefficients of silicon substrates and GaN differ — stress will be generated during the process due to lattice mismatch between the two materials, resulting in bow and crack. In the past, it has not been widely applied in the industry, but it cannot be denied that, owing to its good conductivity and lower heat generation, it helps simplify the thermal design of products.

　　2012 Japan LED Market Development

　　Regarding the development of the Japanese market, he pointed out that in 2011, the LED market was affected by both sluggish end-demand and the power-restriction policy triggered by the Japan earthquake. LED's share of the Japanese lighting market has already exceeded 50%. Currently, under brand-competition pressure, the price of Japanese light bulbs is around 2,500–3,000 yen, while LED bulbs with a wide beam angle still stay at around 4,000 yen, and market acceptance has improved compared with before.

　　Besides price considerations, because Japanese consumers prefer warm-white light colors, light color remains a rather important factor for consumers; therefore, the improvement of color rendering and the uniformity of light quality are also points being emphasized. However, the development of the LED backlight market is worrying. Originally, under highly optimistic expectations, overall market demand fell short of forecasts, which has led panel makers to successively cut shipment volumes, or even shut down and sell off their businesses. Therefore, most manufacturers are also hoping that the Eco-Point system can be relaunched in winter—in addition to addressing winter electricity use, they also hope to maintain demand in LED end-application markets through subsidies.