Active Member
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[China]
Address: No.99 Tong Xi Road, Caijia Town, Beibei District, Chongqing，China
Contact name:Wu
Chongqing Silian Optoelectronic Science & Technology Co., Ltd. |
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4 Inch Sapphire Substrate Is Widely Used
The epitaxial layers of GaN-based materials and devices are mainly grown on sapphire substrates. Sapphire substrate has many advantages: firstly, the production technology of sapphire substrate is mature and the device quality is good; secondly, sapphire is very stable and can be used in the high-temperature growth process; finally, sapphire has high mechanical strength and is easy to handle And cleaning. Therefore, most processes generally use sapphire as the substrate.
| Item | 4" | Unit | |||
| Dimension | Diameter: | 100 ± 0.15 | mm | ||
| Thickness: | 650 ± 20 | um | |||
| Primary Flat: | 30＋1.0 | mm | |||
| Orientation | Surface-cut: | C plane : Tilt 0.2°±0.1° in M axis / | ~ | ||
| Primary Flat: | A plane : 0° ± 0.15° | ~ | |||
| Flatness | Bow: | 0 ~ (-10) | um | ||
| Warp: | ≤ 20 | um | |||
| Total Thickness Variation (TTV): | ≤ 10 | um | |||
| LTV | ≤2.5 | um | |||
| Front side Roughness | ≤0.2 | nm | |||
| Back side Roughness | 0.8-1.2 | um | |||
| Cleanliness | No particles and fingerprints | ~ | |||
| 4.Material Quality | High-purity mono-crystal Al2O3 | ~ | |||
| 5.Package | Wafers are packed in cleaned wafer cassettes containing 25 wafers under clean room environment. | ~ | |||
| 6.Trace Ability | Wafers shall be traceable with respect to cassette number. The wafer box should be marked with a removable label showing the date, the cassette number and the quantity. | ~ | |||
| 7.Laser Mark | Front or Back side | ~ | |||
Working principle
The working principle of the LED is that in the case of forward conduction, the electrons and holes injected into the P/N section of the diode meet and recombine, and the potential energy is converted into light energy. The wavelength of the emitted photons (that is, the color of light) is determined by the energy band width of the semiconductor. The current blue and green LED devices are based on group III nitride semiconductors, which is mainly GaN, and InNAlN is the supplementary four. Yuan AlGaInN alloy system.
To epitaxially grow a GaN film on a sapphire substrate, firstly a two-step epitaxial GaN buffer layer on the substrate (low-temperature epitaxial GaN nucleation layer, then high-temperature epitaxial u-GaN buffer layer); the second step is to grow Si-doped n-GaN The third step is to grow a multifunctional quantum well to provide a radiation recombination center, allowing electrons and holes to recombine and emit light; the fourth step to grow a Mg-doped p-GaN layer to provide hole injection. Normally, the LED structure is as shown in the picture.
