The authors investigate the focused ion beam (FIB) fabrication of photonic crystal (PhC) holes in InP combining physical sputtering using 30 keV gallium ions and iodine-enhanced etching at 150 degrees C with a protective platinum or tungsten layer. The authors show that it is equivalent to conventional dry-etching methods such as inductively coupled plasma reactive ion etching in terms of achievable aspect ratio (>10), surface roughness (12.6 nm rms), and stoichiometry. The protective layers can be selectively removed after fabrication. This new FIB fabrication method lifts the previous constraints of funnel-shaped holes and limited aspect ratios of physical sputtering and reduces the Ga implantation and amorphous layer. Thus, rapid prototyping (5 s fabrication time per hole) of planar PhCs or planar PhC elements, such as PhC Y splitters, becomes feasible. (c) 2007 American Vacuum Society.