PAM-XIAMEN, one of LED wafer manufacturers, offers GaN Wafer for Fabricating LED Devices, which is GaN Epi Structure with InGaN MQWs on sapphire substrate, and can be blue or green emission:
1. Specification of GaN Wafer for LED Devices
No1. PAM200614-GAN-LED
size : 2 inch
WD : 455 ± 10nm
brightness : > 90mcd
VF : < 3.3V
n-GaN Thickness : <4.1㎛
u-GaN thickness : <2.2㎛
substrate : patterned sapphire substrate (PSS)
without p-roughness
without ITO
Single-side polished
Blue LED Structure on Sapphire Wafer Using InGaN/GaN Quantum Well
| p-GaN | Mesa Etching Depth: ~10,000A |
| InGaN MQWs | |
| ESD protection Layer ( -06 μm) | — |
| n-GaN (~4 μm) | — |
| u-GaN (~2 μm) | — |
| Sapphire ( 430 μm) | — |
No.2 GaN/AlGaN/AlGaN Stacked Multilayers on Sapphire Substrate (PAM170107-GOS)
| Composition | Thickness |
| n-SiGaN | – |
| n-AlGaN | 30nm |
| 6 periods of GaN | – |
| InGaN | – |
| p-Mg:GaN | – |
| GaN | 20nm |
| c-plane Sapphire |
No.3 InGaN/GaN Stacked on Sapphire (PAM170107-GOS)
| Composition | Thickness |
| p-Mg:GaN | – |
| 6 periods of GaN | 7nm |
| InGaN | – |
| n-Si:GaN | 2um |
| GaN | – |
| c-plane sapphire |
2. Standard of Gallium Nitride based Epitaxial Layer for LED Lighting
GaN Epitaxial wafers include LED full-structure GaN epitaxial wafers and GaN templates (including n-type and p-type GaN wafers according to conductivity types). Here we just list the criteria of GaN wafer for LED fabrication with the full structure.
2.1 GaN LED Wafer Technical Parameters
The technical parameters of GaN wafer for LED should be complied with the parameters in Table 1.
Table 1
| Item | Requirements (mm) | |||
| 50,8 | 76.2 | 100 | 150 | |
| Diameter | 50.8±0.2 | 76.2±0.2 | 100±0.2 | 150±0.2 |
| Reference Surface Size | 16.0±1.0 | 24.0±1.0 | 32.0±1.0 | 48.0±1.0 |
| Center Point Thickness | 0.43±0.03 | 0.52±0.03 | 0.65±0.03 | 1.30±0.03 |
| Thickness Unevenness | ≤0.02 | ≤0.03 | ≤0.05 | ≤0.08 |
| Curvature | ≤0.04 | ≤0.05 | ≤0.06 | ≤0.08 |
| Warpage | ≤0.04 | ≤0.05 | ≤0.06 | ≤0.08 |
| Note: When the buyer has special requirements for the geometric dimensions of the epitaxial wafer, it shall be specified in the contract by both the supplier and the buyer. | ||||
2.2 GaN Wafer Epitaxial Surface Quality
The surface quality of GaN on Sapphire substrate should be meet the requirements in the Table 2.
Table 2
| Item | Test Conditions | Range | Requirements | |||
| 50.8 mm | 76.2 mm | 100 mm | 150 mm | |||
| Hexagonal defects | 200X | diameter ≥300 um | 0 pcs/wafer | 0 pcs/wafer | 0 pcs/wafer | 0 pcs/wafer |
| diameter <300 um | 20 pcs/wafer | 30 pcs/wafer | 40 pcs/wafer | 60 pcs/wafer | ||
| Fine pits | 200X | diameter ≥ 20 um | 0 pcs/wafer | 0 pcs/wafer | 0 pcs/wafer | 0 pcs/wafer |
| diameter <20 um | 100 pcs/wafer | 150 pcs/wafer | 200 pcs/wafer | 300 pcs/wafer | ||
| Small marks | 50X | length ≥ 5 mm | 0 pcs/wafer | 0 pcs/wafer | 0 pcs/wafer | 0 pcs/wafer |
| length <5 mm | 3 pcs/wafer | 5 pcs/wafer | 10 pcs/wafer | 20 pcs/wafer | ||
| White point | 50X | length ≥ 3 mm | 0 pcs/wafer | 0 pcs/wafer | 0 pcs/wafer | 0 pcs/wafer |
| length <3 mm | 20 pcs/wafer | 30 pcs/wafer | 40 pcs/wafer | 60 pcs/wafer | ||
| Note: When the customer has special requirements for the surface quality of the epitaxial wafer, the supplier and the buyer shall determine in the contract. | ||||||
2.3 Emission wavelength of GaN LED Epi Wafer
The emission wavelength of the full-structure GaN epitaxial wafer is 200nm~430nm for ultraviolet (including violet light), 430nm to 490nm for blue light, and 490nm to 540nm for green light. The typical emission wavelength of the epitaxial wafer of gallium nitride should meet the requirements of Table 3.
Table 3
| Item | Requirement | ||
| UV LED Epitaxial Wafer | Blue LED Epitaxial Wafer | Green LED Epitaxial Wafer | |
| Typical Wavelength /nm | 280±10, 310±10, 380±10 | 450±10, 470±10 | 500±10, 520±10 |
| Note: When the buyer has special requirements for the wavelength of the epitaxial wafer or technological advancement changes the existing wavelength, it shall be specified in the contract by the supplier and the buyer. | |||
2.4 LED GaN Wafer Photoelectric Parameters
The photoelectric parameters such as the opening voltage (VF), peak wavelength, leakage current, electrostatic discharge sensitivity (ESD) of the GaN epi wafer for LED should meet the requirements of Table 4.
Table 4
| Item | Requirements | ||
| UV LED Epitaxial Wafer | Blue LED Epitaxial Wafer | Green LED Epitaxial Wafer | |
| Turn on Voltage / V | ≤5.0 | ≤3.0 | ≤3.0 |
| Peak Wavelength / nm | 280±10, 310±10, 380±10 | 450±10, 470±10 | 500±10, 520±10 |
| Leakage Current(-8V) / uA | ≤0.5 | ≤1 | ≤3 |
| ESD / V | ≥4000 | ≥4 000 | ≥4 000 |
| Note: When the buyer has special requirements for the photoelectric parameters of the GaN epitaxial film or the parameters are changed by technological progress, the supply and buyer shall determine in the contract. | |||
3. FAQ about GaN Epi on Sapphire
Q1: Can you also grow InGaN based LEDs on 2-inch sapphire substrates showing light emission of 600nm or longer?
A: For InGaN MQWs,the wavelength should be <=530nm, nobody can offer above 590nm. Unless you accept GaAs-LED structure.
Q2: I have all information I need for the green LED structure in order to complete the mesa etching but in case of blue LED structure, I don’t have the thickness of the active region (SL+MQW); is it 200nm like the Green LED structure?
A: Regarding green LED structure: SL+MQW is 200nm, etching depth:1.5um.
Q3: Regarding to GaN LED wafer on sapphire, I need to clarify the two points stated in the proforma about [Mg] and RTA.
I guess the Mg level in the cap is much higher than 1-3×10^(18) (I need something in the high 10^19). If this is not the case, the I-V characteristics will be really bad.
Can you please double-check on the level of Mg, or just send me the I-V characteristics of processed LEDs on same epiwafers with the LED size.
Concerning RTA, I want the wafers not activated and I want to activate them myself here.
A: Doping concentration of Mg in GaN on sapphire LED epiwafers is (1-5)E20, activation efficiency of Mg is 1%, after activation, the Mg concentration is (1-5)E18.
Please see below I-V curve：
Q4: Can you show GaN epi layer thickness, dopant, carrier concentration, (hole measurement, CV measurement, etc.), flatness; monitor and actual inspection and evaluation of pits and foreign substances after epi growth; and periodic inspection of metal contamination, ability, etc.?
A: About testing for GaN wafers before shipment:
Regarding GaN substrate: we will test dislocation density for each wafer. We test carrier concentration by HALL by sampling. Undoped one is ~2E17, Si doped one is ~1E18.
The test results of cadmium, lead, mercury, hexavalent chromium, polybrominated biphenyls (PBBs), polybrominated diphenyl ethers (PBDEs), phthalates (such as dibutyl phthalate (DBP), butylbenzyl phthalate (BBP), di (2-ethylhexyl) phthalate (DEHP) and diisobutyl phthalate (DiBP)) meet the limit requirements of the revised Directive (EU) 2015 / 863 of annex 1I of RoHS directive 2011 / 65 / EU. (201028)
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