Surface studies of carbon films from pyrolyzed photoresist

Positive and negative photoresists, which are commonly used in the semicond uctor industry, were deposited on silicon wafers by spin coating and then p yrolyzed at temperatures of 600-1100 degreesC in an inert environment to pr oduce thin carbon films. Raman spectroscopy, X-ray photoelectron spectrosco py (XPS) and scanning probe microscopy involving current-sensing atomic for ce microscopy (CS-AFM) were utilized to characterize the properties of the carbon films. Raman spectroscopy showed two broad bands at approximately 13 60 cm(-1) and 1600 cm(-1), which deconvoluted to four Gaussian bands. The o rigin of these bands is discussed. CS-AFM showed that the surface conductan ce increased with increased pyrolysis temperature, and the results are cons istent with measurements by a four-point probe method. The XPS spectra reve aled the presence of oxygen functional groups (C=O and C-O) on the carbon s urface. The relative fraction of oxygen, O/C ratio, decreased as the pyroly sis temperature increased, in agreement with published results. The full-wi dth at half-maximum of the C-1s peak obtained by XPS also decreased with in creasing pyrolysis temperature. (C) 2001 Elsevier Science B.V. All rights r eserved.