Surface studies of carbon films from pyrolyzed photoresist

Positive and negative photoresists, which are commonly used in the semiconductor industry, were deposited on silicon wafers by spin coating and then pyrolyzed at temperatures of 600-1100 degreesC in an inert environment to produce thin carbon films. Raman spectroscopy, X-ray photoelectron spectroscopy (XPS) and scanning probe microscopy involving current-sensing atomic force microscopy (CS-AFM) were utilized to characterize the properties of the carbon films. Raman spectroscopy showed two broad bands at approximately 1360 cm(-1) and 1600 cm(-1), which deconvoluted to four Gaussian bands. The origin of these bands is discussed. CS-AFM showed that the surface conductance increased with increased pyrolysis temperature, and the results are consistent with measurements by a four-point probe method. The XPS spectra revealed the presence of oxygen functional groups (C=O and C-O) on the carbon surface. The relative fraction of oxygen, O/C ratio, decreased as the pyrolysis temperature increased, in agreement with published results. The full-width at half-maximum of the C-1s peak obtained by XPS also decreased with increasing pyrolysis temperature. (C) 2001 Elsevier Science B.V. All rights reserved.