Yuji Ushijima

Title: Yuji Ushijima: Inventor of Polycrystalline Silicon Carbide Technologies.

Introduction

Yuji Ushijima is an inventor based in Tokyo, Japan, associated with Tokai Carbon. His patent work focuses on polycrystalline silicon carbide (SiC), including its electrical properties and methods of production. He is listed as an inventor on 2 patents.

Latest Patents

One of Ushijima’s listed inventions concerns a nitrogen-doped polycrystalline SiC film with an average grain size of 0.5 to 5 micrometers, produced by chemical vapor deposition (CVD) on a heated base material. The invention addresses the challenge of achieving low volume resistivity while maintaining small crystal grains. Its disclosed molded body has an average grain size of no more than 5 micrometers, a specified nitrogen concentration, and a defined carrier-density and Hall-mobility product.

Another listed invention, “Polycrystalline SiC article,” describes a molded body with resistivity no greater than 0.050 Ω·cm. It also specifies a Raman-spectrum peak ratio of no more than 0.100, comparing peaks in the 760–780 cm⁻¹ and 790–800 cm⁻¹ ranges. These characteristics provide measurable criteria for the material’s electrical and structural properties.

Career Highlights

Ushijima’s listed patent contributions center on engineering polycrystalline SiC materials and controlling their grain size, nitrogen content, resistivity, and Raman-spectrum characteristics. His work is associated with Tokai Carbon, a company connected to the development of carbon and related materials.

Collaborations

Takaomi Sugihara and Seiichi Okuyama are identified as Ushijima’s coworkers. Their names are provided as professional associations, without further details about specific joint projects.

Conclusion

Yuji Ushijima’s patent work highlights approaches to producing and characterizing polycrystalline SiC, with particular attention to small grain sizes and electrical performance.