Nonlinear optics and spectroscopic ellipsometry as complementary sensors to monitor and control SiGe growth

Due to their unique sensitivity to surfaces and interfaces, nonlinear optical techniques such as second harmonic (SH) and sum frequency generation (SFG) have emerged as powerful and highly versatile spectroscopic probes. With the recent availability of commercial, tunable, femtosecond laser systems, in-situ, real-time monitoring of the optical SH responses of Si(OO1) and SiGe(OO1) systems has become possible. Such investigations have included single-wavelength SHG monitoring of CVD growth chemistry, including H coverage and desorption at Si(OO1) in real-time. Spectroscopic SH information around the E1 region of Si is presented that demonstrates adsorbate specific sensitivity to ML coverages.