Influence of silane flow on MOVPE grown GaN on sapphire substrate by an in situ SiN treatment

Halidou, I.; Benzarti, Z.; Boufaden, T.; Jani, B. El; Juillaguet, Sandrine; Ramonda, Michel

doi:10.1016/j.mseb.2004.02.002

Cited by 29 publications

(17 citation statements)

References 20 publications

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“…During the growth of HT-GaN on a conventional buffer layer using an atmospheric pressure MOVPE vertical reactor, we noticed that the use of hydrogen in the carrier gas resulted in a poor surface morphology of the layer [4]. This was also noticed by Haffouz et al [5].…”

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confidence: 61%

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Analysis of GaN decomposition in an atmospheric MOVPE vertical reactor

Fathallah

Boufaden

Jani

2007

Phys. Status Solidi (c)

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The GaN decomposition versus the annealing ambient (H 2 , N 2 + H 2 ) have been investigated in atmospheric pressure metal organic vapor phase epitaxy (AP-MOVPE) vertical reactor. A comparison between the low temperature GaN (LT-GaN) decomposition in a vertical reactor and a horizontal one was discussed in order to explain the failure of high temperature GaN (HT-GaN) growth on Al 2 O 3 using 2D buffer layer under a mixture of H 2 and N 2 in our vertical reactor. Decomposition rates versus temperature and ambient gas were measured using real time laser reflectometry. The surfaces of these films were analyzed using a scanning electron microscopy (SEM). Hydrogen seems to considerably affect the LT-GaN surface morphology by a mass transport, diffusion on the substrate surface and by a decomposition process even in the presence of ammonia and nitrogen. The high decomposition rates of the LT-GaN measured in comparison to that determined for the HT-GaN one is attributed to the amorphous-like structure of the layer and the instability of Ga-N bonds. This favors the appearance of a mirror-like gallium surface in the beginning of this layer decomposition. The presence of liquid gallium catalyzes the decomposition process. HT-GaN SEM analysis revealed that the surface of the "totally" decomposed GaN surface is dominated by gallium droplets. These were removed. The region around and under these droplets is capped by a porous like GaN film. The coalesced gallium droplets may cover some areas of partially decomposed GaN and preserve them from H 2 attack and total decomposition.

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confidence: 61%

“…Hydrogen (H 2 ) and nitrogen (N 2 ) were used as carrier gases. The growth and the decomposition processes were in-situ monitored by He-Ne laser reflectometry (λ = 632.8 nm) [4,6,8]. The samples were ex-situ characterized by SEM.…”

mentioning

confidence: 99%

Analysis of GaN decomposition in an atmospheric MOVPE vertical reactor

Fathallah

Boufaden

Jani

2007

Phys. Status Solidi (c)

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“…More details of the growth process and the optimum growth conditions have been reported elsewhere. [12][13][14] Ex situ reflectivity measurements were performed at room temperature in air for all samples. Polychromatic light from a halogen lamp was used as the light source.…”

Section: Methodsmentioning

confidence: 99%

Study of Surface and Interface Roughness of GaN-Based Films Using Spectral Reflectance Measurements

Benzarti

Khelifi

Halidou

et al. 2015

Journal of Elec Materi

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GaN films were grown using SiN treatment of sapphire substrate by metalorganic vapor-phase epitaxy in a home-made vertical reactor at atmospheric pressure. The growth was interrupted at different stages to investigate the impact of interface and surface roughness on the optical properties of the GaN layers. A transition from a three-dimensional (3D) to two-dimensional (2D) growth mode was revealed by real-time in situ laser reflectometry (k = 632.8 nm) as well as by atomic force microscopy images. A theoretical model is proposed to determine the refractive index evolution during GaN layer growth based on the Bruggeman effective medium approximation. Ex situ multiwavelength reflectivity signals were fit to the thin-film interference equations to derive the evolution of the effective refractive indexes for the surface and interface GaN layer, thereby determining the refractive index of the GaN layer during growth. Ex situ spectroscopic ellipsometry measurements of the GaN layer refractive indexes at different growth stages were compared with calculated results. Moreover, an empirical law was developed to fit the refractive index evolution during GaN layer growth and used for in situ reflectivity signal simulation in order to deduce the growth rate. Finally, good agreement was observed between the experimental and theoretical findings.

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“…After a temperature ramp from 600 to 1120 °C, GaN epilayer was finally grow. Details of the growth process and optimum growth conditions were reported elsewhere [6,7]. The growth was monitored in situ by laser reflectometry (λ = 632.8 nm).…”

Section: Methodsmentioning

confidence: 99%

GaN property evolution at all stages of MOVPE Si/N treatment growth

Halidou

Benzarti

Fitouri

et al. 2007

Phys. Status Solidi (c)

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An investigation of MOVPE GaN growth on sapphire (0001) using Si/N treatment is reported. The growth was monitored in situ He-Ne laser reflectometry. By fitting the reflectivity signal, we derived expressions for the refractive index variation of both sapphire substrate and GaN as a function of the temperature. The morphological and optical property evolutions of the layer at all the growth stages were studied by atomic force microscopy (AFM) and transmittance measurements. A good agreement between AFM images and laser reflectometry signal is obtained. During the island growth and coalescence as clearly revealed by AFM images of the GaN layers, the transmittance signal evolves from featureless characteristic to a signal with regular oscillations.

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Influence of silane flow on MOVPE grown GaN on sapphire substrate by an in situ SiN treatment

Cited by 29 publications

References 20 publications

Analysis of GaN decomposition in an atmospheric MOVPE vertical reactor

Analysis of GaN decomposition in an atmospheric MOVPE vertical reactor

Study of Surface and Interface Roughness of GaN-Based Films Using Spectral Reflectance Measurements

GaN property evolution at all stages of MOVPE Si/N treatment growth

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