He started two publicly traded semiconductor companies, Novellus Systems and Mattson Technology, and has also worked in the solar power industry.

[2] After graduating San Jose State University, Mattson took a job with Applied Materials as a field service engineer.

[citation needed] With new financing to expand operations, Mattson grew Novellus into one of the top three CVD equipment companies in the late 1980s.

Novellus supplied CVD systems to semiconductor producers like Motorola, Advanced Micro Devices, NEC, and LSI Logic.

Novellus Systems was acquired by Lam Research in 2011 for $3.3 billion[6] While taking a break from work in the late 1980s, Mattson began investing in companies on the side.

[9][10] While at the company, Mattson was a finalist for the Ernst & Young Entrepreneur of the Year Award of Northern California in the "High Technology-Electronics" category.

"[13] That same year, Mattson served as a judge for The Tech Awards's Environment category and the theme of "technology benefiting humanity".

Mattson halted the company's plans to build a factory in Oregon, and instead ramped-up R&D to develop copper indium gallium selenide (CIGS) solar technology.