Structure, optical properties and resistance to laser radiation of thin barium disilicide films grown on silicon

Abstract

Polycrystalline and oriented films of barium disilicide (BaSi2) with a thickness of up to 100 nm were formed on silicon (111) substrates by high-temperature (800 ° C) solid-phase (single-stage and two-stage) annealing. The single phase of barium disilicide films and their semiconductor nature have been proven to be below 1.25 eV according to X-ray and optical spectroscopic methods. Two preferential orientations of the BaSi2 crystallites were detected and their orientation was determined in the films formed by two-stage annealing. According to the calculations of the parameters of the crystal structure of BaSi2 films, a compression of the unit cell volume from 2.7% to 5.13% was found, depending on the cooling time to room temperature. The stability of the films to laser radiation was studied by registering the Raman spectra with a variable power of laser radiation. The maximum power density of the laser beam (3⋅109 W/m2), which does not lead to the beginning of the destruction of these films, was determined.

SPE grown BaSi2on Si(111) substrates: optical and photoelectric properties of films and diode heterostructures on their base

“…Let us look at the optical properties of BaSi 2 films grown by two-stage annealing at temperatures of 600 °C and 800 °C with different cooling times to reduce the cracking. 20) In the far infrared region of the transmission spectrum, peaks with minimum positions at 108, 119, 146, 280, and 354 cm −1 were observed, which are in good agreement with the bulk trigonal BaSi 2 . [22][23][24] This is consistent with the good crystalline quality of BaSi 2 crystallites according to the XRD data.…”

“…[22][23][24] This is consistent with the good crystalline quality of BaSi 2 crystallites according to the XRD data. 20) An estimation of the thicknesses of BaSi 2 films based on the ratio of the amplitudes of silicon and silicide peaks according to the XRD data showed that sample No. 2 has a thickness of about 100 nm, and sample No.…”

“…Details of the growth procedure and features of the grown samples, source calibration, and structure were previously described. 20) The following deposition rates were established in growth experiments: 0.6 nm min −1 for Ba and 0.4 nm min −1 for Si, that correspond to Ba/Si deposition rate ratio of 1.5. 21) The co-deposition of 20 nm of Ba and Si were used in the formation of the BaSi 2 templates at 600 °C.…”

“…Photospectral measurements of the formed device structures were carried out at room temperature and at 80 K using standard equipment. 20)…”

“…In our previous work, we used the method of high-temperature (800 °C) solid-phase (one-stage and two-stage) annealing on a Si (111) substrate to form 100 nm thick BaSi 2 polycrystalline films, for which the structure was studied and the temperature stability limits were established under the laser beam. 20) In this paper, we studied and analyzed the relationship between the optical properties of BaSi 2 films grown by solidstate epitaxy on a Si(111) substrate and the photoelectric properties of photodiodes based on them. Also, the energy band diagram was constructed, and the nature of the IR photoresponse of BaSi 2 -n/Si-n heterostructures was analyzed.…”