A focused Ga+ ion-beam (FIB) writing system has been used to directly chang
e an insulating platinum oxide film into a conducting film with a dose in t
he order of 10(14) Ga+/cm(2) at 30 keV ion energy. The sheet resistance of
a PtO2 film, which is prepared by magnetron sputtering, was reduced from 4
x 10(9) Omega/square to approximately 5 x 10(2) Omega/square. Electron micr
oprobe measurements indicate that oxygen loss in the irradiated regions cau
ses the large decrease in resistivity. Scanning electron microscope picture
s show that the film quality after ion irradiation is more homogeneous than
after laser irradiation, which has been used to pattern these materials by
thermal processes. Compared with laser patterning, the resolution of FIB p
atterning is more than one order of magnitude higher and is suitable for po
ssible applications in nanotechnology. (C) 2000 American Institute of Physi
cs. [S0003-6951(00)00123-6].