GaN LED Epi on Sapphire

GaN LED Epi on Sapphire

Powerway Wafer offers III-nitride GaN LED Epi wafer on flat or patterned Sapphire as listed below, which emits blue or green lights. The GaN LED market size is 50mm, 100mm, 150mm or 200mm. The GaN LED emission wavelength can reach 530nm.

A high crystal quality GaN can be gained by depositing a buffer layer at low temperatures. Because of such high quality GaN, the p-type GaN, p-n junction blue/UV-LED and room temperature stimulated emission are discovered.

GaN LED Epi Wafer

1. Specifications of GaN Blue/Green LED Epi Wafer

Item 1:

100mm wafers of blue GaN LED epi layer on c-plane sapphire, 445-475nm (PAM-191010-GaN-LED);

Item 2:

100mm wafers of green GaN LED epi layer on c-plane sapphire, 510-530nm;

Item 3(PAM-190320-blue GaN LED wafer ):

Blue emitting GaN on sapphire commercial LED wafers with maximum output power and the backside polished, which is for compound semiconductor device manufacture;

2. Parameters of GaN LED Epi Wafer on Sapphire

The parameters of GaN LED epi wafer on sapphire are below:

Cassette No. Wafer ID Substrate Wd Avg Wd Std FWHM Avg Chip size Vf(20ma) IV(mcd) IR Yield ESD Yield (HBM 2000)
3    (25pcs) 26 CDGB01A26 CSS(Polished) 452.759 1.477 20.00 7*9mil 156.465 98.22% 96.44%
27 CDGB01A27 CSS(Polished) 0.598 20.00 3.11 98.22%
28 CDGB01A28 CSS(Polished) 1.346 20.00 7*9mil 3.11 156.293 96.44%
29 CDGB01A29 CSS(Polished) 452.813 1.016 7*9mil 3.11 98.22%
30 CDGB01A30 CSS(Polished) 0.863 20.00 7*9mil 3.11 96.44%
31 CDGB01A31 CSS(Polished) 451.508 20.00 3.11 156.05 96.44%
32 CDGB01A32 CSS(Polished) 1.077 20.00 7*9mil 3.11 156.05 96.44%
33 CDGB01A33 CSS(Polished) 450.334 1.141 20.00 7*9mil 98.22% 96.44%
34 CDGB01A34 CSS(Polished) 0.797 20.00 3.11 156.066 98.22%
35 CDGB01A35 CSS(Polished) 0.818 20.00 3.11 155.976 96.44%
36 CDGB01A36 CSS(Polished) 451.113 20.00 7*9mil 98.22% 96.44%
37 CDGB01A37 CSS(Polished) 451.331 1.263 3.11 98.22% 96.44%
38 CDGB01A38 CSS(Polished) 451.857 1.65 20.00 7*9mil 155.937 96.44%
39 CDGB01A39 CSS(Polished) 20.00 7*9mil 3.11 155.959 98.22% 96.44%
40 CDGB01A40 CSS(Polished) 452.425 1.071 20.00 7*9mil 3.11 98.22%
41 CDGB01A41 CSS(Polished) 453.066 1.381 7*9mil 156.027 96.44%
42 CDGB01A42 CSS(Polished) 0.88 7*9mil 3.11 155.98 96.44%
43 CDGB01A43 CSS(Polished) 453.176 1.204 20.00 3.11 98.22%
44 CDGB01A44 CSS(Polished) 453.966 20.00 7*9mil 98.22%
45 CDGB01A45 CSS(Polished) 453.89 0.958 7*9mil 3.11 155.88
46 CDGB01A46 CSS(Polished) 453.932 20.00 7*9mil 155.846 98.22% 96.44%
47 CDGB01A47 CSS(Polished) 1.335 20.00 7*9mil 98.22% 96.44%
48 CDGB01A48 CSS(Polished) 453.948 0.903 20.00 96.44%
49 CDGB01A49 CSS(Polished) 0.923 7*9mil
50 CDGB01A50 CSS(Polished) 1.304 20.00 7*9mil 98.22%


3. GaN LED Epi Process

The basic principle of epitaxial growth is that on a substrate (mainly sapphire (Al2O3) and SiC, Si) heated to an appropriate temperature, gaseous substances In, Ga, Al, and P are transported to the surface of the substrate in a controlled manner. A specific single crystal thin film is grown. At present, the LED epitaxy growth technology mainly adopts MOCVD method.

The substrate material used by most companies now is sapphire (Al203) for GaN LED Epi wafer. Although it has a character mismatch of 13.8% with GaN, the GaN thin film material grown on the sapphire substrate will have a very high dislocation density. However, the cost is low, relatively mature technology, and good stability at high temperature.

4. FAQ for GaN LED Epi Wafer

Q1: What is the typical rms roughness of the polished sapphire backside surface?

Answer: It depends on your application.

Q2: Our application is to fabricate microLED devices using the epi-wafer and perform Laser Liftoff to release the devices for mass transfer and assembly. Could you kindly provide details of the thickness of each layer of the epi stack for both the Green and blue (such as total thickness of the epi-layer on sapphire, thickness of p-GaN, active region, n-GaN and the underlying u-GaN layer etc.)?

Answer: Yes, for laser liftoff application, it should be specific requirement on surface, for more information, please consult our engineer team:

Q3: 1. These new wafers are 2 inch blue LED wafers on sapphire substrates?

      2. These new wafers are annealed (activated) and backside polished so that I can use them straightaway?

      3. These new LED wafers’ qualities (especially the output power) are the same or even better compared with the wafers I bought last time?

Answer: You requirement is: backside polished; annealed; for high power; if so, we recommend you new wafers, but it is 4”size: wavelength:475+/-5nm.

Q4: We need blue LED wafer for laser lift off(LLO) process.

If you have suitable specification wafer, we would like to get samples.

Could you give us information of spec.?

And if you have LLO experience, could you give us information?

Answer: We have some clients requesting LED wafer for laser lift off for micro LED application. For LLO, the wafers needs backside polished, which is some difficult, as during the process, it would be risky for scratch the surface.

There are two options:

Option1: LED wafer on flat sapphire, back side polished.

Option2: LED wafer on patterned sapphire, back side polished.

Q5: Do you think you could let us know if the p-GaN activation was done with in-situ anneal or ex-situ RTA process ?

Answer: We have already done a simple annealing when Mocvd is growing. This is what you call in-situ annealing, but the time is not long enough. So the chip will assist in annealing. Now all the chip processes are like this. My epitaxial wafer can go through the normal chip program.
I don’t know if the in-situ rta program you are referring to is annealed at the end of the chip with an annealing furnace. If so, then my LED/PSS epitaxial wafer does not go through this annealing.

Q6:Could you also give me some information for 4″ blue GaN LED wafers related to:

1. Current vs.output power curve;

2. Light emission spectrum of your product?

Answer: The current vs.output power curve and light emission spectrum of our blue GaN LED epi wafer are shown as figures 1 & 2, which are part of the complete data. For more comprehensive data please contact the sales team .(190809)

Characteristic Curve of Blue GaN LED Epi Wafer

Fig.1 Characteristic Curve of Blue GaN LED Epi Wafer

Light emission spectrum of blue GaN LED wafer

Fig.2 Light Emission Spectrum of Blue GaN LED Wafer

Q7: Do you have any IQE data (IQE is a measurement of optical performance of LED stack ) about your LED epistack, is it possible to get this IQE data, do we have to pay additional fees to get them?

Anwser: The general test method is normal temperature PL test, and calculate the ratio calculation efficiency. IQE method is usually used by scientific research institutes or research institutes, there will be an additional charge, this is mainly because to test in liquid nitrogen environment, the environment is relatively special.


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