Volume 84, Issue 8, 15 October 1998
Index of content:
84(1998); http://dx.doi.org/10.1063/1.368703View Description Hide Description
The infrared modes of annealed alloys were studied experimentally and theoretically. The alloys were grown on Si(100) substrates by solid-source molecular beam epitaxy and were characterized by Fourier transform infrared spectroscopy. At annealing temperatures above the localized vibrational mode of substitutional C around diminished in intensity while another mode due to incoherent siliconcarbide precipitates appeared at For lower processing temperatures, a peak around has been tentatively attributed to a C-rich phase, which is a precursor to SiCprecipitation.Theoretical calculations based on the anharmonic Keating model predict that small (1 nm) 3C–SiC coherent precipitates may actually produce a mode at This mode occurs if the bonds gradually vary in length between the C-rich region and the host lattice. On the other hand, if the bonds are abruptly distorted at the edges of the precipitate, it becomes elastically isolated from the host lattice, and the mode appears. This study yields a picture of the thermal stability of dilute SiC alloys, which is important for the high-temperature processing steps necessary for device applications. Moreover, the coherent precipitation may provide a controllable way to form self-assembled 3C–SiC quantum dots into silicon germanium carbon alloys.
84(1998); http://dx.doi.org/10.1063/1.368690View Description Hide Description
We report here on the electrical characterization of devices, where the films were ion implanted with boron. The current–voltage characteristics versus temperature demonstrated the creation of heterojunctions and Schottky diodes. Maximum current outputs were reached faster for higher temperatures. Lower doses of boronimplants produced Schottky diodecharacteristics, with a current saturation in the forward region due to the existing barrier. The values of the output currents increased with temperature and implanted dose.
84(1998); http://dx.doi.org/10.1063/1.368691View Description Hide Description
The tunability of the band offset in buried GaAs/AlGaAs(001) heterojunctions through insertion of Si interface layers is tested by means of transport techniques. We find that Si diffusion and segregation play a dominant role in spite of the relatively low growth temperatures employed so that band-offset modification will be hindered in practical devices.