Single-crystal layers of AlN have been grown on sapphire substrates between 1000 and 1100 °C by vapor-phase reaction of aluminum chlorides with ammonia. The purity, color, crystallinity, growth morphology, and electrical resistivity of the epitaxial layers have been investigated. Infrared specular reflection measurements showed the presence of an appreciable strain at the AIN-sapphire epitaxy interface. Optical absorption data strongly suggest the AlN is a direct band-gap material with a value of about 6.2 eV at room temperature.

Several models of boron neutralized by atomic hydrogen in silicon were tested by secondary ion mass spectrometry and infrared spectrometry. The hydrogen concentration is comparable to that of boron. Boron neutralization appears as a drop in free-carrier absorption and as an increase in resistivity. A new infrared vibrational mode attributed to 〈111〉 vibrations of H tied to Si appears at 1875 cm−1.

Optical and photoconductive properties of discharge-produced amorphous silicon (a-Si) of the type used in efficient thin-film solar cells have been studied as a function of a wide range of deposition conditions. The optical absorption, optical band gap, photoconductivity, hydrogen content, and the characteristics of the Si-H vibrational mode in a-Si were determined. Both substrate temperature in the range ∼200–400 °C and the type of discharge used are found to be important factors in determining the measured optical and photoconductive properties of a-Si. For films produced at substrate temperatures near 200 °C, dihydride bonding occurs, and the optical band gap is about 1.7 eV. As the substrate temerature increases, monohydride bonding is favored, the optical band gap decreases, the optical absorption increases, and the photoconductive properties improve. These properties are, in part, associated with the presence of bonded hydrogen. For substrate temperatures between 300 and 400 °C, the photoconductive properties are not strongly affected by changes in the substrate temperature, but are strongly influenced by the deposition technique. The Si-H bond is shown to be stable to thermal treatments at or below the deposition temperature. This is critical for the stability of a-Si properties in the fabrication of solar cells and other devices at elevated temperatures.

The reflectance of silicon measured at 4.3 eV can be used to determine the surface quality of silicon. Crystallographic damage, which occurs with abrasive polishing, and texture, which occurs with epitaxial film growth, can be detected. The effect of surface damage on the optical reflectance of silicon measured at 4.3 eV is reported. The reflectance measurement is nondestructive, simple, fast (on the order of seconds), and sensitive. The technique is readily adaptable to quality control inspection in silicon device manufacturing facilities.

discussion of these differences based on these experimental data above.It can be consequently concluded from the experimental results that this delineation method is effective and useful for investigating the lateral diffusion length of As and P in poly-Si. AcknowledgmentsThe authors wish to thank Mamoru Kondo and Eisuke Arai for their encouragement and helpful discussions.