Boron surfactant enhanced growth of thin Si films on CaF2∕Si

Abstract

Boron surfactant enhanced solid-phase epitaxy (SPE) of thin Si films on CaF2∕Si(111) substrates has been studied. Two different growth processes were investigated. In the first process, 1ML of boron atoms was predeposited on the CaF2 surface at room temperature before Si evaporation followed by an anneal to 635°C. This resulted in Si cluster formation. The surface morphology of the Si layer did not show any improvement compared to SPE without surfactant. In the second process, boron atoms were deposited directly on top of the amorphous Si film. This resulted in continuous and smooth epitaxial Si layers on CaF2 with a sharp B-induced (3×3)R30° surface reconstruction after annealing.

Effects of deposition rate on the structure and electron density of evaporated BaSi2 films

“…Surfactant effects of B impurity are reported for Si and Ge growth. 36,37 Despite cracking of films on the high-resistivity substrate, the sample shows negative Hall voltages. This is the evidence of the existence of an n-type layer in the Si substrate near the interface as depicted in Fig.…”

Biaxially oriented CaF2 films on amorphous substrates

“…In the present work, we focus on the creation of biaxial CaF 2 films using the oblique angle deposition technique on Si wafers covered with a layer of amorphous native oxide. CaF 2 has been known as an excellent buffer layer material for the growth of a variety of semiconductor materials including Si [10][11][12][13][14] and compound semiconductors [15][16][17]. The heteroepitaxial structures with CaF 2 have promising applications in many advanced devices [14], such as resonant tunneling diodes [12] and electrooptical modulators [14,18].…”

Fabrication of single-crystalline insulator∕Si∕insulator nanostructures

“…In this context, the basic considerations for the insulator as barrier are sufficiently large conduction and valence band offsets with respect to Si of ⌬E Ͼ 1 eV, a good lattice match, and a crystal structure compatible to Si. 19,21 But such procedures limit the applicability of the nanostructure because of the incorporation of the surfactant atoms, which often act also as dopants in Si. 1-4͒ and some rare-earth metal oxides ͑REMOs͒, such as Y 2 O 3 , 5 ͑La x Y 1−x ͒ 2 O 3 , 6 Pr 2 O 3 , 7,8 and CeO 2 , 9,10 for which epitaxial growth on Si͑111͒ has also been reported.…”