Hokkaido University Research Profiles


high-precision machining technology: 1

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  • 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.


    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.