Near-field etching on diamond mesa

Our paper was published in physica status solidi (a)

Takashi Yatsui, Daisuke Takeuchi, Satoshi Koizumi, Kazuki Sato, Kohei Tsuzuki, Takayuki Iwasaki, Mutsuko Hatano, Toshiharu Makino, Masahiko Ogura, Hiromitsu Kato, Hideyo Okushi, and Satoshi Yamasaki, “Polarization-controlled dressed-photon–phonon etching of patterned diamond structures,” physica status solidi (a), Vol. 211, No. 10, October 2014, pp. 2339–2342, DOI: 10.1002/pssa.201431161

[Significance of this article]

Diamond has many excellent characteristics that make it an ideal material for high-performance power devices. For diamond-based devices such as diamond p-n junctions, the device must be constructed on a patterned substrate, but the final device should have smooth surfaces. Unfortunately, because of the hardness of diamond, ultra-flat surfaces are difficult to obtain. We developed a non-contact polishing method for realizing ultra-flat material surfaces: dressed-photon and phonon etching (DPP etching). In this study, we utilize DPP etching to produce ultra-flat surfaces on a three-dimensional diamond structure. By controlling the polarization of the incident light, we could obtain a smooth sidewall on the diamond mesa structure. We achieved the highest etching rates using an oblique incident angle of 45˚ with respect to the diamond substrate with polarization perpendicular to the corrugation on the mesa sidewall. We further confirmed the smoothness of the surface using selective deposition of n-layer diamond on the p-layer diamond mesa structure. Therefore, we believe DPP etching is an essential technique for realizing high-performance diamond devices.