Abstract

Surface second harmonic generation (SSHG) from the Si-SiO₂ interface is of considerable interest because it is sensitive to surface steps [1], straining of subsurface bonds [2] and surface roughness [3], all of which are important in the fabrication of integrated circuits. By using 10 fs pulses we are able to obtain acceptable signal to noise ratio using less than 30 mW, as compared to the hundreds of mW necessary for 100 fsec pulses [1,3]. The p-polarized pulses (45° incident angle) are generated by a Kerr-lens-modelocked Ti: sapphire laser [4]. Additionally the very broadband nature of these pulses allows us to observe resonance behavior in the SSHG by simply spectrally resolving the SSHG, i.e., tuning the laser is not required.

© 1996 Optical Society of America