Growth Of InN Films Research Articles

Growth of narrow substrate temperature window on the crystalline quality of InN epilayers on AlN/Si(1 1 1) substrates using RF-MOMBE

Epitaxial InN films were grown on AlN/TMAl seed layer/Si(1 1 1) substrates in the range of temperature between 500 and 540 °C using pulsed-mode RF-MOMBE. The structural properties of the InN films were characterized using X-ray diffraction (XRD), field-emission scanning electron microscopy, and transmission electron microscopy (TEM). The electrical properties were characterized by Hall effect measurements. The results indicated that small changes in temperature significantly affect the quality of InN films. The XRD and TEM results indicated that the InN films grew oriented along the c-axis. Phi-scan XRD patterns indicated that the InN films grew epitaxially on the Si(1 1 1) substrates with the orientation relationship InN [1 1 −2 0]InN//[11 0]Si. When the substrate temperature at 530 °C, the TEM images indicated three-dimensional InN/AlN growth and growth rate was approximately 0.2 μm/h. The cross-sectional TEM images and SAD pattern showed a sharp InN/AlN interface and clear epitaxial orientation relationships of InN (−2 1 1 0)InN//(−2 1 1 0)AlN//(2 –2 0)Si, [0 0 0 1]InN//[0 0 0 1]AlN//[1 1 1]Si. The electron concentrations of the InN films were measured from 5.5 × 1019 to 1.3 × 1020 cm−3, and the mobility was measured from 116 to 360 cm2/V·s. The results indicate that controlling the substrate temperature is essential for engineering the growth of InN films on silicon wafers.

Sputtered growth of high mobility InN thin films on different substrates using Cu-ZnO buffer layer

This work reports the growth of c-plane textured InN thin films on Cu-ZnO buffered silicon, c-sapphire, bulk GaN and quartz substrates. A Cu-ZnO buffer layer was deposited on all the substrates before the growth of InN film. A highly c textured film was obtained on sapphire and quartz substrates. Structural properties were calculated using XRD and Raman analysis. It was observed that, induction of Cu-ZnO buffer layer reduced the lattice mismatch between Si/GaN substrates and InN film. The bandgap of the films was obtained using UV visible reflectance spectroscopy. Hall measurements show high mobility films in the range of 119–223cm2/Vs and an electron concentration of 1019. These results are in good agreement with previous results but are first time recorded using RF magnetron sputtering. Surface topography of the films showed smooth surfaces, which are due to reduced lattice mismatch between film and the substrate.

Growth of InN films by radical-enhanced metal organic chemical vapor deposition at a low temperature of 200 °C

The InN films were deposited on GaN surfaces at a low temperature of 200 °C by radical-enhanced metal organic chemical vapor deposition (REMOCVD). The REMOCVD system can provide N radicals from the plasma of a N2–H2 mixture gas without using ammonia. Two types of GaN substrate, bulk GaN and GaN on Si(111), were used. The growth mode was modeled as a step flow on the basis of surface morphology observation by atomic force microscopy.

High-quality InN films on GaN using graded InGaN buffers by MBE

The growth of high-quality thick InN films is challenging because of the lack of native substrates. In this work, we demonstrate the use of a linearly graded InGaN buffer layer for the growth of InN films on GaN substrates. A 500 nm InN film with <0.1 nm RMS roughness is obtained with a peak mobility of 1410 cm2/(V·s) at 300 K. A strong room temperature photoluminescence showing a bandgap of 0.65 eV with 79 meV linewidth is observed. A graded InGaN buffer is found to lead to extremely smooth and high-quality InN films.

Impact of substrate nitridation on the growth of InN on In2O3(111) by plasma-assisted molecular beam epitaxy

We study the growth of InN films on In2O3(111) substrates by plasma-assisted molecular beam epitaxy under N excess. InN films deposited directly on In2O3(111) exhibit a strongly faceted morphology. A nitridation step prior to growth is found to convert the In2O3(111) surface to InN{0001}. The morphology of InN films deposited on such nitridated In2O3(111) substrates is characteristic for growth by instable step-flow and is thus drastically different from the three-dimensional growth obtained without nitridation. We show that this change originates from the different polarity of the films: while InN films deposited directly on In2O3(111) are In-polar, they are N-polar when grown on the nitridated substrate.

Microstructures of InN film on 4H-SiC (0001) substrate grown by RF-MBE**Project supported by the Thailand Center of Excellence in Physics (ThEP) and the King Mongkut's University of Technology Thonburi under The National Research University Project. One of the authors (S. Sanorpim) was supported by the National Research Council of Thailand (NRCT) and the Thai Government Stimulus Package 2 (TKK2555), under

InN film was grown on 4H-SiC (0001) substrate by RF plasma-assisted molecular beam epitaxy (RF-MBE). Prior to the growth of InN film, an InN buffer layer with a thickness of ∼5.5 nm was grown on the substrate. Surface morphology, microstructure and structural quality of InN film were investigated. Micro-structural defects, such as stacking faults and anti-phase domain in InN film were carefully investigated using transmission electron microscopy (TEM). The results show that a high density of line contrasts, parallel to the growth direction (c-axis), was clearly observed in the grown InN film. Dark field TEM images recorded with diffraction vectors and g = 0002 revealed that such line contrasts evolved from a coalescence of the adjacent misoriented islands during the initial stage of the InN nucleation on the substrate surface. This InN nucleation also led to a generation of anti-phase domains.

Initial experiments in the migration enhanced afterglow growth of gallium and indium nitride

AbstractSome initial results are presented for gallium nitride and indium nitride thin films grown on c‐plane sapphire using a prototype migration enhanced afterglow (MEAglow) system. Smooth surfaces of less than 1 nm root mean square surface roughness have been achieved for both InN and GaN films at growth temperatures of 450‐560 °C and 665 °C respectively. This result is attributed to the increased adatom diffusion length allowed for the metal species during the growth process. Thicker GaN layers can now be grown than those previously reported. For InN, an impressive full width half maximum value of 290 arcsec has been achieved for the (0002) reflection using ω−2θ X‐ray diffraction scans. Greater progress has so far been achieved for the growth of InN films because of the relative ease with which thick layers of indium metal can be nitrided to form a good quality layer. (© 2012 WILEY‐VCH Verlag GmbH &amp; Co. KGaA, Weinheim)

Low-temperature growth of highly c-oriented InN films on glass substrates with ECR-PEMOCVD

High quality InN films are deposited with an interlayer of high c-orientation (002) AZO (Aluminium-doped Zinc Oxide; ZnO:Al) films on glass substrates by electron cyclotron resonance plasma-enhanced metal organic chemical vapor deposition (ECR-PEMOCVD) at low temperature. AZO films used as a buffer layer are effective for the epitaxial growth of InN films. The influence of Trimethyl Indium (TMIn) flux on the properties of InN films is systematically investigated by reflection high energy electron diffraction (RHEED), X-ray diffraction analysis (XRD), atomic force microscopy (AFM) and optical transmittance spectra. The results indicate that high quality InN films with high c-orientation and small surface roughness are successfully achieved at an optimized Trimethyl Indium (TMIn) flux of 5.5 sccm. The InN/AZO structures have great potential for the development of full spectra solar cells.

Growth Orientation Control of Semipolar InN Films Using Yttria-Stabilized Zirconia Substrates

We have investigated the epitaxial growth of InN films on yttria-stabilized zirconia (YSZ) substrates with various surface orientations. Through systematic crystallographic investigations, we have found that the epitaxial relationship of InN[1120] ∥YSZ [110] and InN[0001] ∥YSZ [111] holds in the InN/YSZ system. This enables us to grow semipolar InN films with arbitrary orientations.

Suppression of indium droplet formation by adding CCl4 during metalorganic chemical vapor deposition growth of InN films

In this work, the influences of CCl4 on the metalorganic chemical vapor deposition (MOCVD) growth of InN were studied for the first time. It was found that the addition of CCl4 can effectively suppress the formation of metal indium (In) droplets during InN growth, which was ascribed to the etching effect of Cl to In. However, with increasing of CCl4 flow, the InN growth rate decreased but the lateral growth of InN islands was enhanced. This provides a possibility of promoting islands coalescence toward a smooth surface of the InN film by MOCVD. The influence of addition of CCl4 on the electrical properties was also investigated.

Growth of InN films and nanostructures by MOVPE

Since a few years, a lot of research efforts have been devoted to InN, the least known of the semiconducting group-III nitrides. Most of the samples available today have been grown using the molecular beam epitaxy technique, and fewer using the metal organic vapor phase epitaxy (MOVPE) method. Whatever the method, the growth of InN is extremely challenging, in particular due to the fact that no lattice matched substrate is available. This paper present results on the improvement of the InN crystal quality in MOVPE. In particular, the use of carbon halides to enhance the lateral growth is demonstrated, leading to extremely smooth InN surfaces. A new process for the realization of InN nanostructures by recrystallization is presented, which allows to obtain a better crystal quality than direct MOVPE growth.

MOVPE growth of InN films using 1,1-dimethylhydrazine as a nitrogen precursor

InN films have been successfully grown on sapphire substrates by MOVPE using trimethylindium (TMIn) and 1,1-dimethylhydrazine (DMHy) with N 2 carrier. DMHy is an advantageous precursor of N as it decomposes efficiently at relatively low temperature ( T 50=420 °C) compatible with the InN growth. The reactor is specially designed so as to avoid parasitic reaction between TMIn and DMHy occurring at room temperature. The growth feature was studied by varying growth temperature, V/III ratio, TMIn flow and reactor pressure. The InN films were obtained at 500–570 °C and 60–200 Torr with a V/III ratio optimized to 100–200. The In droplets are seen on the grown surfaces, indicating an excess supply of TMIn. It is demonstrated that the InN films grows on the sapphire substrate in a single domain with an epitaxial relationship, [1 01¯ 0] InN//[1 1 2¯ 0] sapphire.

Effect of polarity on the growth of InN films by metalorganic chemical vapor deposition

The effect of surface polarity on InN growth on GaN by metalorganic chemical vapor deposition (MOCVD) was investigated. The polarity of the InN was found to follow that of the initial GaN template as determined by a comparison of experimental and simulated convergent beam electron diffraction patterns. Under identical MOCVD growth conditions, In-polar InN was observed to nucleate and grow on Ga-polar GaN as pyramidal-shaped islands with (101¯1) as the stable surface facet. In contrast, enhanced lateral growth and reduced surface roughness were observed for N-polar InN grown on N-polar GaN. InN films grown on (0001) sapphire substrates using a thin AlN buffer under identical conditions to those used for growth on the GaN templates also exhibited reduced surface roughnesses and were determined to be N polar. A qualitative model based on the difference in surface terminations and crystal structures is proposed to explain the observed differences in the structural properties and growth modes of the In-polar and N-polar InN films.

Influence of growth temperature and V/III ratio on the optical characteristics of narrow band gap (0.77 eV) InN grown on GaN/sapphire using pulsed MOVPE

In this study, we report on the pulsed metalorganic vapor phase epitaxy (MOVPE) of InN as well as the optical and electronic properties of the films as a function of V/III ratio and growth temperatures. The growth of InN films was conducted utilizing a vertical reactor with TMIn and NH 3 as the In- and N-precursors, respectively. Metallic droplet-free InN films were achieved on GaN/sapphire template in a pulsed MOVPE mode with low V/III ratio condition. In the pulsed growth mode, NH 3 was constantly flowing while the TMIn was sent into the reactor chamber for a 36-s pulse and then it bypassed the reactor chamber for an 18-s pulse for a total cycle time of 54 s. At a growth pressure of 200 Torr, the effects of growth temperature (510–575 °C) and V/III ratio (12,460–17,100) on the photoluminescence (PL) transitions were investigated. Morphological evolution as well as the electrical quality of the overgrown films have also been studied for the given growth conditions.

The effect of rf power on the growth of InN films by modified activated reactive evaporation

We report the effect of rf power on the structural, optical and electrical properties of InN films grown by modified activated reactive evaporation. In this technique, the substrates were kept on the cathode instead of ground electrode. The films grown at higher rf power shows preferential c-axis orientations for both silicon and glass substrates. The films prepared at 100 W show best structural, electrical and optical properties. The c-axis lattice constant was found to decrease with increase in rf power which can be attributed to reduction in excess nitrogen in the films. The band gap decreases with increase in rf power due to Moss–Burstein shift. The decrease in carrier concentration and optical band gap with increase in rf power can also be related to excess nitrogen in the film. The Raman spectra shows a red shift in the A 1(LO) and E 2 (high) mode from the reported value. The possible origin of the present large band gap is due to Moss–Burstein shift. The new film growth method opens opportunities for integrating novel substrate materials with group III nitride technologies.

Influence of Different Interlayers on Growth Mode and Properties of InN by MOVPE

We grow InN epilayers on different interlayers by metal organic vapour phase epitaxy (MOVPE) method, and investigate the effect of interlayer on the properties and growth mode of InN films. Three InN samples were deposited on nitrided sapphire, low-temperature InN (LT-InN) and high-temperature GaN (HT-GaN), respectively. The InN layer grown directly on nitrided sapphire owns the narrowest x-ray diffraction rocking curve (XRC) width of 300 arcsec among the three samples, and demonstrates a two-dimensional (2D) step-flow-like lateral growth mode, which is much different from the three-dimensional (3D) pillar-like growth mode of LT-InN and HT-GaN buffered samples. It seems that mismatch tensile strain is helpful for the lateral epitaxy of InN film, whereas compressive strain promotes the vertical growth of InN films.

Growth of InN films on spinel substrates by pulsed laser deposition

AbstractWe have grown InN films on MgAl2O4(111) substrates with atomically flat surfaces using pulsed laser deposition (PLD) and compared their structural properties with those grown on (Mn,Zn)Fe2O4(111) substrates. It has been revealed that InN(0001) films grow on MgAl2O4(111) with an in‐plane epitaxial relationship of InN[1$ \bar 1 $00] // MgAl2O4[1$ \bar 1 $0], achieving a lattice mismatch minimum. The InN films exhibited a clear sixfold rotational symmetry, without 30° rotational domains and with a full width at half maximum value of the InN 0002 rocking curve being 17.5 arcmin. Comparison between InN films grown on MgAl2O4 and those on (Mn,Zn)Fe2O4 led us to conclude that suppression of the interfacial reactions between the InN films and the substrate is inherently important to obtain high quality InN on substrates with a spinel structure. (© 2007 WILEY‐VCH Verlag GmbH &amp; Co. KGaA, Weinheim)

Epitaxial Growth of InN Films by Molecular-Beam Epitaxy Using Hydrazoic Acid (HN3) as an Efficient Nitrogen Source

Epitaxial InN films have been successfully grown on c-plane GaN template by gas-source molecular-beam epitaxy with hydrazoic acid (HN3) as an efficient nitrogen source. Results in residual-gas analyzer show that the HN3 is highly dissociated to produce nitrogen radicals and can be controlled in the amounts of active nitrogen species by tuning HN3 pressure. A flat and high-purity InN epifilm has been realized at the temperature near 550 degrees C, and a growth rate of 200 nm/hr is also achieved. Moreover, the epitaxial relationship of the InN(002) on the GaN(002) is reflected in the X-ray diffraction, and the full-width at half-maximum of the InN(002) peak as narrow as 0.05 degrees is related to a high-quality crystallinity. An infrared photoluminescence (PL) emission peak at 0.705 eV and the integrated intensity increasing linearly with excitation power suggest that the observed PL can be attributed to a free-to-bound recombination.

Initial stages of the cubic-InN growth with the technique of the pre-deposition of indium

The initial stages of the cubic indium nitride film growth at 350 °C were studied using low-pressure metal-organic chemical vapor deposition. The technique of the pre-deposition of indium was applied, that is, a layer of indium was first deposited on sapphire surface before the growth of InN. X-ray diffraction and X-ray photoelectron spectroscopy show that the pre-deposition of indium is able to promote the growth of InN films, and meanwhile, suppress the indium aggregation in the as-grown films. Atomic force microscopy images of InN films indicate that the pre-deposition of indium not only enhances the density of nucleate sites, but also facilitates the coalescence among the InN islands. The free energy calculations reveal that the pre-deposited indium atoms preferentially react with NH and N radicals after NH3 introduction, which leads to the formation of InN on the sapphire surface. The preferentially formed InN is then supposed to be responsible for the above phenomena.

Growth of InN films and nanorods by H-MOVPE

InN films and nanorods were grown by hydride metalorganic vapor phase epitaxy (H-MOVPE) and the effects of growth temperature, and NH 3/TMIn and HCl/TMIn ratios on morphological dependences were studied. The growth habit of InN varied from thin film to microrod to nanorod to no deposition as the growth conditions were changed about transition from growth to etching conditions. The growth and etch regimes were also predicted by chemical equilibrium calculations of In–C–H–Cl–N-inert system. The optical properties of InN nanorods and columnar structured films were measured by room temperature PL and a maximum intensity was observed at 1.08 eV for both structures.