LASER PROJECTION PATTERNING FOR THE FORMATION OF THIN-FILM DIAMOND MICROSTRUCTURES

Projection patterned excimer laser radiation at 193 nn has been used t o etch free-standing polycrystalline diamond films. Excellent lateral reproduction of images down to 2 lan has been achieved, but features e volve with a side wall. that slopes at around 25 degrees to the normal ; this limits the depth of each feature in relation to its lateral dim ension. However, three-dimensional microgears, with a diameter of 930 mu m, have been successfully fabricated using this technique. Patterni ng in air gives rise to etch rates as high as 31 nm per laser pulse, b ut in an evacuated environment this is reduced to around 0.6 nm; furth ermore, Raman spectra indicate that patterning in vacuo leaves strongl y modified surfaces, whilst air processing causes little degradation t o the diamond film.