Semiconductor photonic crystals are expected to realize the ultimate control of spontaneous emission, so-called Purcell effect. However, there are two important issues. One is a fine dry etching process for a high aspect ratio over 10 in submicron period structures. The other is a surface treatment for the reduction in surface recombination. With regard to these issues we have studied InP-based materials, since they have a low surface recombination velocity ν_s. We developed the etching process using the inductively coupled plasma. The surface recombination was evaluated through the lifetime measurement of photoluminescence at a wavelength over 1 µm using the phase resolved spectroscopy. We investigated various surface treatments and found that the CH₄ plasma irradiation is effective for realizing crucial ν_s of 1×10³ cm/s order. The SIMS analysis suggests that it is due to the electronic insulation near the surface by the shallow implantation of C.