Photoemission from metal conductors in integrated circuits has previously been used as a microscopic probe of circuit performance.1 We demonstrate the novel use of photoemission for microscopic probing of the material characteristics on a semiconductor surface. A focused UV laser beam is scanned across a patterned semiconductor, and differences in surface properties such as doping or oxide/metal deposits are observed as differences in emitted photocurrent. This new technique has several potential advantages over other possible methods for mapping out microscopic surface properties. For example, to measure doping one could use micro-SIMS, but this has the disadvantage of being a destructive technique. Raman spectroscopy signals are affected by doping,2 but this effect is large only for highly doped p-type silicon and/or long wavelengths.
© 1989 Optical Society of AmericaPDF Article