Leadership

Takehiko Hosoi earned a Bachelor of Science degree in Mechanical Engineering from Waseda University in 1986. Following graduation, he joined Kawasaki Steel Corporation in Japan and was assigned to NBK Corporation in Santa Clara, California, where he worked as a Process Engineer specializing in crystal growth technology. In 1996, he relocated to Phoenix, Arizona, to join Sumitomo Sitix of Phoenix (SPX), where he played an instrumental role in launching and scaling the company’s crystal growth manufacturing operations.

In 2003, he returned to Japan and joined the Crystal Engineering Department. There, he contributed to the development of crystal growth processes for 200 mm and 300 mm volume production, as well as 450 mm research and development initiatives. Over the next 23 years, he held a series of technical and leadership positions of increasing responsibility, culminating in his appointment as General Manager of the Crystal Engineering Department at SUMCO.

In 2025, Takehiko was promoted to Managing Executive Officer, assuming responsibility for the company’s global crystal production and engineering operations. In March 2026, he returned to Phoenix, Arizona, for a second assignment to serve as Chairman, President, and Chief Executive Officer of SPX.

---

In 1993, shortly after graduating from the University of Dayton with a Bachelor of Science degree in Business Administration, Don started his career with SUMCO as a Staff Accountant in the former Sumitomo Sitix Cincinnati plant. In 1996 he moved to manufacturing after being promoted to Supervisor and then Assistant Production Manager in the Substrate Operation. He joined the sales group in 1998, where he has held several roles including Customer Support Supervisor, Senior Sales Manager and Director of Sales. Don relocated to Phoenix in 2018 and was promoted to Vice President of Sales and Marketing in 2024, then Senior Vice President of Sales and Marketing in 2025.

---

Masataka Kimura graduated from Osaka Prefecture University with a Master’s Degree specializing in Applied Chemistry.  He was hired by Mitsubishi Metal Corporation in 1988 and transferred to Japan Silicon as an Epi Engineer.  He continued his work as an Epi Engineer at the Chitose plant and then moved to Noda plant in 2001 as an Application Engineer at Mitsubishi Materials Silicon.  Masataka returned back to the Chitose plant as Manufacturing Manager in 2004, then he moved to the SUMCO Cincinnati location as Director of Epi Engineering and Manufacturing in 2009 and back to Chitose plant in 2011.  He relocated to the Imari plant in 2017 as Director of TPM Promotion Department and returned back to the United States to SUMCO Albuquerque to serve as Vice President of Epi Operations in 2018. In 2023 Masataka relocated to Phoenix, Arizona when promoted to Senior Vice President Quality, Technology, IT and EHS.

---

Danny Kohanek has been with SUMCO since 1999 and has extensive experience in our manufacturing process. Danny started his career in silicon manufacturing with Motorola in 1983 as a production operator. Then in 1993 started his journey in Management as Shift Supervisor and was promoted several years later to Manufacturing Manager. Motorola sold its business to Mitsubishi Material in 1998 and Danny was recruited from Motorola to work at the Salem South Plant in 1999. He transferred from SUMCO Oregon in 2004 to Phoenix as Manufacturing Manager and was promoted to Director of Manufacturing in 2016. Upon completing his Bachelors in Business Administration from the University of Phoenix in 2021, Danny was promoted to Senior Vice President of Manufacturing.

---

Greg joined SPX as the Corporate Accounting Manager in July of 2002 and has 30+ years of experience in the areas of Finance, Accounting and Tax. Prior to joining SPX, Greg held accounting management roles in the Washington, DC area for a technology company, an oil and gas trading company and an airline food caterer.  Greg earned a Bachelors of Science degree in accounting and his CPA license (inactive status) in the state of Maryland.