Diamond was successfully synthesized using a low pressure, radio frequency (r.f.), inductively-coupled plasma (ICP). A source mixture of methanol (CH3OH), hydrogen (H-2), and water vapor (H2O) was introduced into the reaction chamber through a quartz tube of 12 mm inner diameter. A seven-turn r.f. coil was mounted on the quartz tube to produce a high-density plasma. The Si substrate was located in a downstream region. Diamond formation was carried out with varying mixture ratios of source gases at total pressures of 9.3-18.6 Pa, an r.f. power of 500 W, a substrate temperature of 700 degrees C, and a substrate bias of +30 V. Diamond crystals exhibiting a well-defined 1332 cm(-1) diamond Raman peak were formed using CH3OH/H-2/H2O mixtures at total pressures below 19 Pa.