Effects of hydrogen on the formation of SiGe/Si heterostructures
In this report, we review and discuss our results obtained on the surface segregation of Ge atoms and surfactant effects of hydrogen atoms in Si overlayer growth on Ge/Si(100) by gas-source molecular beam epitaxy (GSMBE) using GeH/sub 4/ and Si/sub 2/H/sub 6/. The layer-by-layer growth rate of the Si overlayers was observed in-situ by reflection high-energy electron diffraction (RHEED) intensity oscillation periods.
Effects of atomic hydrogen on growth behavior of Si films by Si2H6-source molecular beam epitaxy
The effect of hydrogen atoms on the segregation of Ge atoms has been investigated in the Si overlayer growth on Ge/Si(100) substrates by gas source molecular beam epitaxy with additional atomic hydrogen. The Ge composition on the growing surfaces decreases exponentially with increasing Si overlayer thickness. The irradiation of excess atomic hydrogen reduces the decay length of the Ge composition, which directly indicates that hydrogen atoms adsorbed on the growing surface play an important role in suppressing the surface segregation of Ge atoms. A unified linear correlation between the decay length of the Ge segregation in Si/Ge/Si(100) and the hydrogen coverage on Si atoms obtained from the Si/Si(100) homoepitaxial growth with additional atomic hydrogen has been obtained. This fact suggests that the exchange between surface Si atoms and subsurface Ge atoms is suppressed by the hydrogen atoms on surface Si atoms.
High-Speed Infrared Radiometers*
The paper describes high-speed infrared radiometers utilizing thermistor infrared detectors. Instruments with 4- and 8-in. diam Cassegrain mirror optics are described. The method of operation and the calibration of these radiometers is discussed.The radiometers are uniformly sensitive from 0.7 to 35 μ. They have a response time of 16 msec and a sensitivity of the order of 10−10 w/cm−2 corresponding to a blackbody temperature differential of 0.01°C.The radiometers are used for quantitative measurements of infrared radiation and remote temperature determinations.