PAM-XIAMEN, one of leading GaN substrate manufacturers, offers 10*10mm2 N-Type Freestanding GaN Substrate. To get more specific information please see the table below:
1. N-Type Freestanding GaN Substrate Specification
|Dimension||10 x 10.5 mm2|
|Orientation||C plane (0001) off angle toward M-axis 0.35 ±0.15°|
|Conduction Type||N-type / Si Doped|
|Resistivity (300K)||< 0.05 Ω·cm|
|TTV||≤ 10 µm|
|BOW||BOW ≤ 10 µm|
|Surface Roughness:||Front side: Ra<0.2nm, epi-ready;
Back side: Fine Ground or polished.
|Dislocation Density||≤5x 106 cm-2 (calculated by CL)*|
|Macro Defect Density||0 cm-2|
|Useable Area||> 90% (edge exclusion)|
|each in single wafer container, under nitrogen atmosphere, packed in class 100 clean room|
2. Standard Method for Testing Bulk GaN Substrate Carrier Concentration
This standard specifies the method for testing the carrier concentration of N-type free-standing GaN substrates by using Raman spectroscopy. In addition, this standard applies to the measurement of carrier concentration of N-type gallium nitride substrates grown on sapphire, silicon carbide, silicon, and gallium nitride materials. The test range should be 1X1017 cm-3~1X1020 cm-3.
2.1 Method Principle for Testing N-Type Freestanding GaN Substrate
At a certain temperature, the atoms in the material lattice each make microvibrations (lattice vibrations) near their equilibrium positions, and the energy of the lattice vibrations is represented by phonons. A certain concentration of carriers in the gallium nitride material interacts with the lattice vibration to form a longitudinal optical phonon-plasmon coupled mode (LO phonon-plasmon coupled mode, referred to as LOPC), which can be used in Raman Feature peaks of low and upper frequency branches (lower and upper frequency branches, often marked as LPP- and LPP+) appear on the spectrum. The peak position of the characteristic peak changes with the change of the carrier concentration, and the carrier concentration can be calculated by the change of the peak position. This method can realize the micro-area measurement of the N-type GaN freestanding substrate carrier concentration of through Raman spectroscopy, and the measurement diameter is 0.7 um~2 um.
2.2 Disturbing Factors for Testing Freestanding GaN Bulk Substrate
There are three main factors affecting the detection accuracy. To get the more accurate data of the carrier concentration of bulk GaN substrate, we should obey the following points:
- Raman spectroscopy is often used to detect the stress in thin film materials, so it is necessary to consider the influence of stress in the test;
- Raman spectrometers are generally equipped with gratings (monochromators). Due to the temperature sensitivity of the gratings, temperature changes will cause the peak position of the measured spectrum to drift. The instrument should be kept in a suitable temperature environment during testing;
- If the surface of the sample is contaminated, especially if there are substances that can cause fluorescence interference, it will affect the quality of the Raman spectroscopy. If the N-type substrate of GaN is not clean, we should use a solvent, such as ethanol, acetone or toluene, to wipe the sample to remove the stains before testing.
Schematic diagram of coupled mode peak shape caused by carriers in N-type freestanding GaN single crystal substrate Raman spectroscopy:
3. Realted Posts about Freestanding Gallium Nitride Film: