Microstructure and electronic properties of the refractory semiconductor ScN grown on MgO(001) by ultra-high-vacuum reactive magnetron sputter deposition

Abstract

Articles you may be interested inThermoelectric properties of epitaxial ScN films deposited by reactive magnetron sputtering onto MgO(001) substrates J. Appl. Phys. 113, 153704 (2013); 10.1063/1.4801886Influence of working gas pressure on structure and properties of WO 3 films reactively deposited by rf magnetron sputtering J.Influence of the target-substrate distance on the properties of indium tin oxide films prepared by radio frequency reactive magnetron sputtering Microstructural evolution and Poisson ratio of epitaxial ScN grown on TiN(001)/MgO(001) by ultrahigh vacuum reactive magnetron sputter deposition ScN layers, 180 nm thick, were grown on MgO͑001͒ substrates at 750°C by ultra-high-vacuum reactive magnetron sputter deposition in pure N 2 discharges. N/Sc ratios, determined by Rutherford backscattering spectroscopy, were 0.98Ϯ0.02. X-ray diffraction -2 scans and pole figures combined with plan-view and cross-sectional transmission electron microscopy showed that the films are strongly textured, both in plane and along the growth direction, and have a columnar microstructure with an average column width near the film surface of 30Ϯ5 nm. During nucleation and the early stages of film growth, the layers consist of approximately equal volume fractions of 002-and 111-oriented grains. However, preferred orientation evolves toward a purely 111 texture within Ӎ40 nm as the 002 grains grow out of existence in a kinetically limited competitive growth mode. 002 grains exhibit local cube-on-cube epitaxy with an orientation relationship (001) ScN ʈ (001) MgO and ͓010͔ ScN ʈ ͓010͔ MgO while 111 grains have a complex fourfold 90°-rotated in-plane preferred orientation in which strained ScN triangular ͕111͖ surface unit cells exhibit local epitaxy with square MgO unit cells yielding the orientation relationship (111) ScN ʈ (001) MgO , ͓110͔ ScN ʈ ͓110͔ MgO , and ͓112͔ ScN ʈ ͓110͔ MgO . Room-temperature electrical resistivity is 1.2 ϫ10 4 ⍀ cm while d/dT was found to be negative, indicating semiconducting behavior, with varying from 1.6ϫ10 4 ⍀ cm at 80 K to 1.1ϫ10 4 ⍀ cm at 400 K. Optical absorption coefficients ranged from 1ϫ10 4 cm Ϫ1 at 1.5 eV to 2.6ϫ10 5 cm Ϫ1 at 3.5 eV with a well-defined edge corresponding to a direct transition at 2.37Ϯ0.05 eV.

Compensation of native donor doping in ScN: Carrier concentration control and p-type ScN

“…4,28-30 (MBE), dc-magnetron sputtering 2,8,31 , hybrid vapor phase epitaxy 5,6,32 (HVPE) and other 33,34 methods have been employed over the years to deposit epitaxial ScN thin films on MgO, Al2O3 (sapphire) and Si substrates 35 . As-deposited ScN thin-film deposited with most of these growth techniques result in n-type semiconductors having a large carrier concentrations in ~10…”

Band gaps of wurtzite ScxGa1−xN alloys

“…ScN is a rock-salt structure semiconductor with a direct band gap of 2.1 eV and an indirect band gap of 0.9 eV [5][6][7] , which can be grown easily by molecular beam epitaxy 8 and which has already been used in as a dislocation reduction interlayer in GaN films 9 and is of interest for thermoelectric applications 8,10,11 . The phase stability, structural and optical properties of ScN and Sc x Ga 1-x N have been calculated previously.…”

Study on the addition of nonmetal interstitial atoms to the yttrium lattice: formation of YBx, YCx and YNx alloys

“…With these particularities their void spaces (interstices) are large enough to fit easily any nonmetal from the first and second row of periodic table [6]. Nevertheless, the number of studies covering their nitrides, carbides and borides is low, although scandium nitride has received attention in the last few years due to its semiconducting characteristics [7][8][9][10][11]. Like ScN, cubic-YN is also an indirect-gap semiconductor when the nitrogen to yttrium ratio is close to one [12].…”