STUDIES ON H-TERMINATED SI(100) SURFACES BY 2ND-HARMONIC GENERATION

We report our experimental results of optical second-harmonic generati on (SHG) from H-terminated Si(100) surfaces. For the clean Si(100)-(2X 1) and the Si(100)(3X1)-H surfaces, the SH intensity decreased monoton ically with increasing temperature in the temperature range 350-700 K and 350-500 K, respectively. For the Si(100)(2X1)-H surface, with incr easing temperature, the SH intensity increased in the temperature rang e 350 to about 470 K, and decreased in the range 470 to about 660 K. T ransformaiton between three phases was found to be reversible. The sur face structure and sample temperature could be monitored by the SHG me asurements.