Raman microprobe analysis of strain induced by patterned dielectric films of GaAlAs structures

Raman spectra from GaAlAs layers with Si/sub 3/N/sub 4/ stripes obtained with a microprobe are discussed. The spatial resolution of these Raman spectra was smaller than the scale of the microfabricated features. A significant stress-induced shift in the GaAlAs longitudinal optic (LO) phonon frequency has been observed under 3.5 mu m wide Si/sub 3/N/sub 4/ stripes. Rapid thermal annealing reduced the LO phonon frequency shift, and thus the stress, under the Si/sub 3/N/sub 4/ stripe. A corresponding dramatic change in optical waveguide behavior under the stripe was observed. >