Single-walled carbon nanotubes have been grown by chemical vapor deposition from methane and hydrogen on catalyst patterns prepared by microcontact printing on 20 nm thick silicon nitride substrates. A higher yield of single-walled carbon nanotubes was obtained by the simple expedient of introducing hydrogen during deposition. Based on atomic force microscopy and transmission electron microscopy measurements, we found that high-quality single-walled carbon nanotubes with a broad diameter distribution were obtained.