Hokkaido University Research Profiles

Manufacturing Technology

Semiconductor Precision Processing Technology

Low-damage and controllable semiconductor etching technology using electrochemical reactions

A semiconductor etching technique using electrochemical reactions was developed to reduce damage and achieve precise processing control in the depth direction compared with conventional methods, and was applied to the gate recess processing of AlGaN/GaN heterostructure transistors to realize normally-off transistors.

Content of research

The etching process of semiconductor surfaces is one of the essential steps in the fabrication of semiconductor devices such as transistors. In this laboratory, we have developed an etching method that is superior to conventional dry etching methods in terms of both depth control and damage suppression, by utilizing electrochemical oxidation and dissolution reactions on semiconductor surfaces. As a result of applying the method to AlGaN/GaN heterostructures, which are considered to be promising power transistor materials, it was revealed that the etching process can be self-stopped at the desired processing depth by optimizing the electrochemical conditions, thus eliminating the need for an etching stop layer, which had been essential in prior technologies, and enabling precise control of the transistor threshold in a simpler way. In addition, the etched surface by this method has less processing damage than the dry-etched surface, and is expected to be a promising method for improving transistor performance.

Potential for social implementation

  • ・Precise control of semiconductor etching
  • ・Transistor threshold control
  • ・Formation of semiconductor nanostructures
  • ・Semiconductor surface damage removal

Appealing points to industry and local governments

We are working on the control of semiconductor electrochemical reactions and device applications, with the focus on III-V compound semiconductors. We would like to collaborate extensively with companies that are interested in introducing electrochemical etching, including joint research and technical guidance.

Intellectual property related to this research

特願2017-095458 「エッチング法及びエッチング装置」