4 Inch Undoped GaN On Flat Or Patterned Sapphire Substrates For Visible LEDs

4 Inch Undoped GaN On Flat Or Patterned Sapphire Substrates For Visible LEDs

PAM-XIAMEN’s Template Products consist of crystalline layers of gallium nitride (GaN), aluminum nitride (AlN),aluminum gallium nitride (AlGaN)and indium gallium nitride (InGaN), which are deposited on sapphire substrates. PAM-XIAMEN’s Template Products enable 20-50% shorter epitaxy cycle times and higher quality epitaxial device layers, with better structural quality and higher thermal conductivity,which can improve devices in the cost, yield, and performance.

PAM-XIAMEN’sGaN on sapphire templates are available in diameters from 2" up to 6",and consist of a thin layer of crystalline GaN grown on a sapphire substrate. Epi-ready templates now available..

Here shows detail specification:
4inch Undoped GaN/Sapphire Substrates

4inch Undoped GaN/Sapphire Substrates
FWHM and XRD report
A test report is necessary to show the compliance between custom description and our final wafers data. We will test the wafer characerization by equipment before shipment, testing surface roughness by atomic force microscope, type by Roman spectra instrument, resistivity by non-contact resistivity testing equipment,micropipe density by polarizing microscope, orientation by X-ray Orientator etc. if the wafers meet the requirement, we will clean and pack them in 100 class clean room, if the wafers do not match the custom spec, we will take it off.

Testing Project: FWHM and XRD project
The half-height full width (FWHM) is an expression of the range of functions given by the difference between two extreme values of the independent variable equal to half of its maximum. In other words, it is the width of the spectral curve measured between those points on the Y-axis, which is half the maximum amplitude.

Below is an example of FWHM and XRD of AlN template:

FWHM and XRD of AlN template


FWHM and XRD of AlN template


Here we show experiment as an example:
Experiment on GaN on sapphire:Optoelectronic Properties and Structural Characterization of GaN Thick Films on Different Substrates through Pulsed Laser Deposition:

Experiment on GaN on sapphire:Optoelectronic Properties and Structural Characterization of GaN Thick Films on Different Substrates through Pulsed Laser Deposition:
All GaN film samples were deposited on different substrates by PLD at 1000 ◦C in a nitrogen plasma ambient atmosphere. The chamber was pumped down to 10−6 Torr before the deposition process began, and N2 gas (with a purity of 99.999%) was introduced. The working pressure once the N2 plasma was injected was 1.13 × 10−4 Torr. A KrF excimer laser (λ = 248 nm, Lambda Physik, Fort Lauderdale, FL, USA) was employed as the ablation source and operated with a repetition rate of 1 Hz and a pulse energy of 60 mJ. The average growth rate of the GaN film was approximately 1 µm/h. The laser beam was incident on a rotating target at an angle of 45◦ . The GaN target was fabricated by HVPE and set at a fixed distance of 9 cm from the substrate before being rotated at 30 rpm during film deposition. In this case, ~4 µm-thick GaN films were grown on a GaN/sapphire template (sample A), sapphire (sample B), Si(111) (sample C), and Si(100) (sample D). For the GaN on sample A, a 2-µm GaN layer was firstly deposited on sapphire substrate by MOCVD. Scanning electron microscopy (SEM, S-3000H, Hitachi, Tokyo, Japan), transmission electron microcopy (TEM, H-600, Hitachi, Tokyo, Japan), atomic force microscopy (AFM, DI-3100, Veeco, New York, NY, USA), double-crystal X-ray diffraction (XRD, X’Pert PRO MRD, PANalytical, Almelo, The Netherlands), low-temperature photoluminescence (PL, Flouromax-3, Horiba, Tokyo, Japan), and Raman spectroscopy (Jobin Yvon, Horiba, Tokyo, Japan) were employed to explore the microstructure and optical properties of the GaN templates deposited on different substrates. The electrical properties of the GaN films were determined by Van der Pauw-Hall measurement under liquid nitrogen cooling at 77 K

To further clarify the stress behaviors among the four samples, Raman scattering spectroscopy was performed, and the results are shown in Figure 6. The E2-high phonon mode is very sensitive to biaxial strain, and is extensively used to characterize the in-plane stress state of the GaN epilayer [33]
The relationship between biaxial stress and Raman shift can be shown by the formula:
where σ is the biaxial stress, ∆ω is the Raman shift, and k is the Raman stress coefficient of 6.2 cm−1 ·GPa−1 for GaN [34]. Generally, a blue shift in an E2-high phonon peak indicates compressive stress, while a red shift indicates tensile stress [35]. It has been found that an E2-high peak position is substrate dependent, which implies that there are different stress states in those samples. In the present case, the GaN E2-high peaks of samples MGS (MOCVD-grown GaN on sapphire), A, B, C, and D were evaluated as 520.7, 569.7, 565.5, 565.7, and 566.3 cm−1 , respectively. Compared to the intrinsic value of 566.8 cm−1 for the stress-free GaN, samples B, C, and D were under tensile stress, while sample A was under compressive stress [36]. This can be due to the rapid release of stress in the nucleation of GaN films during the initial growth by high-temperature (1000 ◦C) PLD. This observed result is also consistent with those reported by Wang et al. [37]. Sample D had minimum stress, likely caused by the growth of polygonal island structures and defects generated in the films, which is consistent with the SEM results [38]. There is a large difference in the lattice mismatch and thermal expansion between GaN and Si when compared to the GaN/sapphire template and sapphire.


Figure 6. Raman spectra of GaN films for samples MGS (metalorganic chemical vapor deposition (MOCVD)-grown GaN on sapphire), A, B, C, and D.

Conclusion: the GaN thick films grown on a GaN/sapphire template, sapphire, Si(111), and Si(100) by high-temperature PLD. The substrate effect on GaN crystalline growth quality, surface morphology, stress behavior, and interface property were studied, if you need more product information, please enquire us.

gallium nitride wafer

gallium nitride gan

4 Inch Undoped GaN On Flat Or Patterned Sapphire Substrates For Visible LEDs Images