Sumitomo Electric files patent lawsuit against AXT
According to its complaint, SEI alleges that AXT-Japan and MO Sangyo sell GaAs substrates in Japan that infringe two of SEI s Japanese patents. Neither AXT-Japan nor MO Sangyo complied with a request from SEI that they halt sales of these particular products in Japan.
SEI s patents relate to its vertical Bridgman (VB) method for the commercial production of GaAs substrates. The company says that there are two major advantages of substrates made by its VB method. These are:
- low residual strain, which enables significant minimization of slip-line defects.
- high resistivity, resulting in excellent device performance due to reduced leak current through a substrate.
SEI obtained one of the patents listed in the complaint (Japanese patent number 3,156,382) in December 2001 for the low residual-strain advantage, and the other patent (Japanese patent number 3,201,305) on its carbon-doping manufacturing method in June 2001.
SEI s complaint, filed on April 15, 2003, asks for an injunction to halt the importation or sale in Japan of GaAs substrates manufactured by AXT that allegedly infringe on SEI s patents. The suit also requests compensation for infringement, to be paid by AXT-Japan and MO Sangyo.
A statement issued by SEI reads, "The demand for improved quality devices requires continuing improvements in wafer quality. At the same time, the pressure for lower cost devices made with SEI substrates requires continuing effort to lower the cost of the wafer.
"Protection of intellectual property is critical to maintaining significant investment for research and development activities to meet the demands of the progressing market."
