CN202996885U

CN202996885U - LED epitaxial wafer growing on Si substrate

Info

Publication number: CN202996885U
Application number: CN 201220686083
Authority: CN
Inventors: 李国强
Original assignee: Guangzhou Zhongtuo Optoelectrical Technology Co Ltd
Current assignee: Guangzhou Zhongtuo Optoelectrical Technology Co Ltd
Priority date: 2012-12-11
Filing date: 2012-12-11
Publication date: 2013-06-12
Anticipated expiration: 2022-12-11

Abstract

The utility model discloses an LED epitaxial wafer growing on a Si substrate. The LED epitaxial wafer growing on the Si substrate is characterized in that the LED epitaxial wafer growing on the Si substrate comprises a Si substrate layer, an Al2O3 protection layer growing on the Si substrate layer, and a u-GaN buffer layer, a n-GaN layer, an InGaN/GaN quantum well layer and a p-GaN layer growing on the Al2O3 protection layer orderly. The LED epitaxial wafer of the utility model possesses excellent electrical and optical properties.

Description

A kind of LED epitaxial wafer that is grown on the Si substrate

Technical field

The utility model relates to a kind of LED epitaxial wafer, is specifically related to the LED epitaxial wafer on a kind of Si of being grown in substrate.

Background technology

The GaN semi-conducting material has excellent photoelectric properties, successfully obtain first p-GaN from I. Akasaki, after realizing the new breakthrough of blue-ray LED, the GaN based compound semiconductor receives much concern always, has a wide range of applications in fields such as room lighting, commercial lighting, engineering illuminations.

The high-quality GaN material is generally all made by heteroepitaxy method.The selection of substrate is very large to the quality influence of epitaxial growth GaN material, generally need to follow the principles such as lattice constant match, matched coefficients of thermal expansion, price be suitable.In addition, different backing materials also have very important impact to the preparation technology of GaN base LED device.For example because the GaN crystal exists the piezoelectricity and spontaneous polarization effect, different substrates can make the material list that obtains reveal different polarization characteristics.In addition, because the different materials price variance is larger, the difference of backing material also can make the cost of LED produce larger difference.This shows, the selection of GaN base LED backing material is most important.

As the substrate that is usually used in growing GaN, sapphire, SiC, Si have realized the preparation of device level LED at present, but the outer layer growth problem brought of backing material separately also needs constantly to capture.Sapphire has stable physicochemical properties, but has very large lattice mismatch (16%) and thermal stress mismatch (25%) between it and GaN, causes the GaN epitaxial layer quality of growth relatively poor.Its heat conductivility is poor simultaneously, and this is also seriously restricting the development of Sapphire Substrate great power LED.Although the lattice mismatch of SiC and GaN only 3.5%, thermal conductivity is higher, and its thermal stress mismatch and sapphire be (25.6%) quite, and be relatively poor with the wetability of GaN, expensive, and manufacturing technology monopolizes by U.S. Cree, therefore also can't generally use.Si by the Novel substrate of people in order to alternative above-mentioned two kinds of substrates, has broad application prospects just for these reasons.At first, the growth technique of Si monocrystal maturation makes available lower cost obtain large-area high-quality Si substrate, reduces the cost of LED device.Secondly, Si has good heat conduction, electric conductivity, can conveniently make the good vertical stratification device of heat radiation.Again, the microelectric technique of Si is very ripe.Therefore Si Grown GaN film is expected to realize photoelectron and microelectronic integrated.

At present, the researcher constantly studies the epitaxy technology of Si Grown GaN both at home and abroad, and has report successfully to prepare LED.Yet although Si has many superiority, the GaN monocrystal thin films quality for preparing on the Si substrate wants that not as Sapphire Substrate the preparation that realizes device level Si base LED also faces many difficult problems.At first, the lattice mismatch of Si and GaN is very large (approximately 16%) still, and suitable with sapphire, the defective in the GaN epitaxial loayer of growing on Si does not have the minimizing of the order of magnitude.Secondly, the thermal coefficient of expansion of Si is 2.61 * 10 ^-6/ K, far away higher than sapphire (approximately-25.5%), can cause like this producing huge tensile stress in epitaxial loayer, thereby more easily cause the be full of cracks of epitaxial loayer up to 114% with the GaN thermal mismatching.Again, can pass into N during epitaxial growth GaN on the Si substrate ₂Gas, because the bond energy of Si-N is very large, the Si substrate is met active N and is easily being formed at the interface unbodied Si _xN _yLayer, this has had a strong impact on the quality of the basic LED device of the GaN that obtains of institute.

This shows, cost is low even if the Si substrate has, good heat dissipation, and conveniently make the advantages such as vertical devices, has very good development prospect, but make the Si substrate GaN-based LED can really realize large-scale application, need to improve the quality of the LED epitaxial wafer of Si Grown, improve optics and the electric property of LED epitaxial wafer by the improvement of structure or technique.

The utility model content

The purpose of this utility model is to overcome the defective of above-mentioned prior art, and a kind of LED epitaxial wafer on the Si substrate of being grown in excellent electricity and optical property is provided.

For achieving the above object, the utility model adopts following technical scheme:

A kind of LED epitaxial wafer that is grown on the Si substrate, it comprises the Si substrate layer, is grown in the Al on the Si substrate layer ₂O ₃Protective layer is grown in Al successively ₂O ₃U-GaN resilient coating on protective layer, n-GaN layer, InGaN/GaN quantum well layer and p-GaN layer.The first Al that grows on the Si substrate layer of the utility model ₂O ₃Protective layer, regrowth GaN thin layer afterwards, Al ₂O ₃Protective layer can prevent effectively that reacting with active N at the interface of Si substrate from forming unbodied Si _xN _yThereby, avoided Si _xN _yThe impact of layer on the GaN growth quality obtains high-quality GaN film.In addition, Al ₂O ₃Protective layer can be alleviated thermal stress mismatch (114%) huge between Si substrate and GaN, prevents that simultaneously Si is diffused in GaN.

Preferably, described Al ₂O ₃The thickness of protective layer is 3-5nm.

Preferably, the thickness of described u-GaN resilient coating is 300-450nm.

Preferably, the thickness of described n-GaN layer is 2.5-3.5 μ m.

Preferably, the thickness of described p-GaN layer is 300-400nm.

Compared with prior art, the beneficial effects of the utility model are:

The utility model uses Si as substrate, and one deck Al first grows on the Si substrate ₂O ₃Protective layer can prevent effectively that Si from forming unbodied Si with active N reaction at the interface _xN _yThereby, avoid Si _xN _yThe impact of layer on the GaN growth quality; In addition, Al ₂O ₃Layer is conducive to alleviate thermal stress mismatch (114%) huge between Si and GaN, prevents that simultaneously Si is diffused in GaN, has improved optics and the electric property of LED epitaxial wafer.

Description of drawings

Fig. 1 is structural representation of the present utility model.

Embodiment

Below in conjunction with the drawings and specific embodiments, the utility model is described in further detail.

Please refer to Fig. 1, the LED epitaxial wafer that is grown on the Si substrate of the present utility model, it comprises Si substrate layer 11, is grown in the Al on Si substrate layer 11 ₂O ₃ Protective layer 12 is at Al ₂O ₃Grow successively u-GaN resilient coating 13, n-GaN layer 14, InGaN/GaN quantum well layer 15 and p-GaN layer 16 on protective layer 12.

In preferred version, described Al ₂O ₃The thickness of protective layer 12 is 3-5nm, and the thickness of described u-GaN resilient coating 13 is 300-450nm, and the thickness of described n-GaN layer 14 is 2.5-3.5 μ m, and the thickness of described p-GaN layer 16 is 300-400nm.

In the utility model, u-GaN resilient coating 13 can provide good template for subsequent growth n-GaN layer 14.

Manufacture method of the present utility model is as follows:

Adopt the Si substrate, adopt the molecular beam epitaxial growth method at Si Grown Al ₂O ₃Protective layer then adopts the pulsed laser deposition growth method to grow successively u-GaN resilient coating, n-GaN layer, InGaN/GaN quantum well layer and p-GaN layer.

Above-described embodiment is only preferred implementation of the present utility model; can not limit protection range of the present utility model with this, the variation of any unsubstantiality that those skilled in the art does on basis of the present utility model and replacement all belong to protection range of the present utility model.

Claims

1. a LED epitaxial wafer that is grown on the Si substrate, is characterized in that: comprise the Si substrate layer, be grown in the Al on the Si substrate layer ₂O ₃Protective layer is grown in Al successively ₂O ₃U-GaN resilient coating on protective layer, n-GaN layer, InGaN/GaN quantum well layer and p-GaN layer.

2. the LED epitaxial wafer that is grown on the Si substrate as claimed in claim 1, is characterized in that: described Al ₂O ₃The thickness of protective layer is 3-5nm.

3. the LED epitaxial wafer that is grown on the Si substrate as claimed in claim 1, it is characterized in that: the thickness of described u-GaN resilient coating is 300-450nm.

4. the LED epitaxial wafer that is grown on the Si substrate as claimed in claim 1, it is characterized in that: the thickness of described p-GaN layer is 300-400nm.