Effects of ZnO interlayers on thick GaN/Si film prepared by RF magnetron sputtering

Zhang, C.G.; Bian, L.F.; Chen, Weidong; Hsu, C. C.

doi:10.1016/j.jcrysgro.2006.05.064

Cited by 11 publications

(7 citation statements)

References 14 publications

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“…The nearly zero intercept seen in the case of the GaN film deposited on ZnO buffer layer shows that the lateral crystallite size in this case is larger than the limit of measurements. The crystallite tilt of~2.5°in sputtered GaN film on ZnO buffer layer over quartz substrate, is comparable to the reported value of~2°for GaN films sputter deposited on ZnO/Si substrates from a Ga 2 O 3 target [51]. The measured value of tilt is about an order of magnitude higher than the reported values (from (0002) rocking curve measurements) for epitaxial GaN films grown over ZnO buffer layers on sapphire substrates by MBE [48], MOCVD [44] and PLD [50,57] techniques.…”

Section: Resultssupporting

confidence: 84%

“…High quality epilayers of GaN have also been deposited on ZnO buffer layer over sapphire substrates, using this approach [44,48,49]. There are also a few reports on the use of ZnO as a buffer layer in the growth of GaN films by sputtering, using GaN [50] and Ga 2 O 3 [51] targets. ZnO has a hexagonal wurtzite structure with lattice constants close to those of GaN (lattice mismatch~1.8%) and polycrystalline ZnO films are known to exhibit strong c-axis orientation of crystallites [52].…”

Section: Introductionmentioning

confidence: 99%

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Highly oriented GaN films grown on ZnO buffer layer over quartz substrates by reactive sputtering of GaAs target

et al. 2008

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Section: Resultssupporting

confidence: 84%

Section: Introductionmentioning

confidence: 99%

Highly oriented GaN films grown on ZnO buffer layer over quartz substrates by reactive sputtering of GaAs target

et al. 2008

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“…Although attractive for its versatility, scalability and viability at relatively lower temperatures, sputtering has not been extensively employed for the growth of GaN, primarily due to the non-availability of suitable targets, since elemental Ga melts near room temperature. Sputtered GaN films have thus been grown by using several target materials, including, Ga [8][9][10][11][12], GaN [13,14], and Ga 2 O 3 [15]. Earlier work from our group has demonstrated the use of GaAs as an alternative target for the growth of nano/polycrystalline [16,17] and epitaxial [18] GaN films by rf reactive magnetron sputtering in 100% N 2 as the sputtering-cum-reactive gas.…”

Section: Introductionmentioning

confidence: 99%

Microstructural dependence of residual stress in reactively sputtered epitaxial GaN films

Monish¹,

Major²

2021

J. Phys. D: Appl. Phys.

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Epitaxial GaN films were grown on c-sapphire by rf magnetron reactive sputtering of GaAs at different partial pressures of nitrogen in Ar–N2 sputtering atmosphere. High-resolution x-ray diffraction and φ-scans reveal the mosaic growth of c-axis oriented, wurtzite GaN films. The c and a parameters were independently determined to obtain the corresponding in-plane and out-of-plane strain components. Raman measurements confirmed the in-plane strain behavior. The surface morphology and elemental composition of films were studied by atomic force microscopy and secondary ion mass spectroscopy, respectively. High-resolution ω-2θ, ω, and in-plane φ-rocking curve scans were used to obtain micro-strain, screw and edge dislocation densities, respectively. The films grown at 30%–100% N2 reveal dominance of edge (∼1012 cm−2) over screw (∼1010 cm−2) dislocations, with both approaching similar densities at lower N2 percentages. The strain data has been analyzed to separate the hydrostatic and biaxial contributions and their dependences on N2 percentage. The film grown at 100% N2 displays large hydrostatic strain and micro-strain due to the presence of excess/interstitial nitrogen. The hydrostatic strain and micro-strain decrease substantially with initial decrease of N2 percentage, but increase slightly in the films grown below 30% N2, primarily due to the incorporation of Ar. The films grown below 75% N2 display growth-related intrinsic tensile stress, originating from crystallite coalescence. The stress reversal from tensile to compressive, seen in the films grown at higher N2 percentages is primarily attributed to the incorporation of excess/interstitial nitrogen into grain boundaries and the tensile side of edge dislocations. The decrease of intrinsic tensile stress in the films grown below 30% N2 is attributed to the incorporation of Ar and their voided structure.

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“…Although the density of threading dislocations has often been limited to the range of 10 6 -10 7 cm −2 in MOCVD [11] and MBE [12] grown GaN films, there are some limitations due to the high temperature operation in MOCVD and issues related to the scalability and high cost of MBE. The low temperature amenability, scalability and versatility of sputtering makes it an appealing option, which has demonstrated considerable potential for the growth of GaN films [13][14][15][16][17][18][19][20], albeit with threading dislocations in the range of 10 9 -10 12 cm −2 [18][19][20]. Accordingly, various modes of sputtering have been employed for the growth of both undoped [18,20,21] and doped (with Si, Ge and Mg) [19,[22][23][24] GaN films.…”

Section: Introductionmentioning

confidence: 99%

Electrical transport in epitaxially grown undoped and Si-doped degenerate GaN films

Monish,

Major

2024

Phys. Scr.

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This study investigates the electrical transport properties of undoped and Si-doped, degenerate GaN heteroepitaxial films grown on sapphire by reactive rf sputtering of GaAs (and Si) in Ar-N2 mixture. The room temperature electrical measurements showed that the resistivity of undoped GaN film grown at 100% N2 was ~2 × 105 Ω cm, which reduced to ~1 Ω cm in Si-doped film, revealing the effect of Si doping. With decrease of N2 from 100% to 75%, the carrier concentration of Si-doped films increased from ~7 × 1018 cm-3 to ~2 × 1019 cm-3, but remained practically unchanged as N2 was decreased to 20%, which is explained by effects due to saturation of Si doping and increase of Ga interstitials as well as compensation by N interstitials and Ga vacancies. Undoped and Si-doped films grown below 20% N2 displayed similar carrier concentrations (~1020 cm-3), due to dominance of Ga interstitials. Both undoped and Si-doped films were degenerate and displayed increase of mobility with carrier concentration and temperature, which was analyzed by the combined effect of ionized impurity and dislocation scattering, using compensation ratio as fitting parameter. At carrier concentrations ≲1019 cm-3, the mobility was governed by both ionized impurity and dislocation scattering, while at higher carrier concentrations, ionized impurity scattering was found to dominate, limited by compensation due to acceptors. In spite of the degenerate character, the films displayed a small decrease of carrier concentration with temperature, along with a nearly linear decrease of mobility, which are explained by a marginal increase of compensation ratio with decrease of temperature, taking into account the band edge fluctuation effects. These features of electrical transport have not been much explored for heteroepitaxial, n-type degenerate GaN films, possessing high density of dislocations and point defects.

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Effects of ZnO interlayers on thick GaN/Si film prepared by RF magnetron sputtering

Cited by 11 publications

References 14 publications

Highly oriented GaN films grown on ZnO buffer layer over quartz substrates by reactive sputtering of GaAs target

Highly oriented GaN films grown on ZnO buffer layer over quartz substrates by reactive sputtering of GaAs target

Microstructural dependence of residual stress in reactively sputtered epitaxial GaN films

Electrical transport in epitaxially grown undoped and Si-doped degenerate GaN films

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