CN101866999B

CN101866999B - Method for preparing zinc oxide-based heterojunction light emitting diode

Info

Publication number: CN101866999B
Application number: CN2010101833705A
Authority: CN
Inventors: 张曙光; 尹志岗; 张兴旺; 游经碧
Original assignee: Institute of Semiconductors of CAS
Current assignee: Institute of Semiconductors of CAS
Priority date: 2010-05-19
Filing date: 2010-05-19
Publication date: 2012-09-05
Anticipated expiration: 2030-05-19
Also published as: CN101866999A

Abstract

The invention provides a method for preparing a zinc oxide (ZnO)-based heterojunction light emitting diode. The method comprises the following steps of: 1) depositing a p-gallium nitride (GaN) thin film on a substrate; 2) growing a ZnO thin film on the p-GaN thin film; 3) etching one side of the ZnO thin film which is grown on the p-GaN thin film off by using a wet etching method to expose the p-GaN thin film and form a mesa; 4) preparing a p-type electrode on the mesa of the p-GaN thin film; and 5) preparing an n-type electrode on the ZnO thin film.

Description

Make the method for zno-based heterojunction light-emitting diode

Technical field

The present invention relates to the semiconductor photoelectronic device technical field, be specifically related to a kind of method of making zno-based heterojunction light-emitting diode.

Background technology

Light-emitting diode is considered to the third generation semiconductor lighting device after incandescent lamp, fluorescent lamp, and the advantage of its efficient and long life has caused people's research enthusiasm greatly.At present, the light-emitting diode of InGaN/GaN base has got into the industrialization stage.ZnO is a kind of important II-VI family broad stopband direct gap semiconductor material; Its bigger energy gap (3.37eV) with high exciton bind energy (60meV); Make its potential Material Used that becomes the short-wave long light-emitting device, have purposes widely in fields such as semiconductor white-light illuminating, optical communication, high density information storages.Do not solve fully as yet so far because the p type ZnO of high hole concentration, high mobility, high duplication prepares a difficult problem, restricted the preparation of zno-based homogeneity light-emitting diode greatly.Therefore and GaN has extremely similar physical property with ZnO, and p-GaN commercialization, has carried out a large amount of work people aspect the preparation of relevant n-ZnO/p-GaN heterojunction light-emitting diode and the property research.The bottleneck that current restriction n-ZnO/p-GaN heterojunction light-emitting diode obtains large-scale application is that its luminous efficiency is not high, and therefore, the luminous efficiency that how to improve ZnO heterojunction light-emitting diode becomes the emphasis of current research.

Summary of the invention

The objective of the invention is to, a kind of method of making zno-based heterojunction light-emitting diode is provided, this method can strengthen the luminous efficiency of heterojunction light-emitting diode greatly, has characteristics such as cost is low, simple to operate, widely applicable, practical.

The present invention provides a kind of method of making zno-based heterojunction light-emitting diode, comprises the steps:

1) deposition p-GaN film on substrate;

2) growing ZnO thin-film on the p-GaN film;

3) adopt wet etching, a side of the ZnO film on the p-GaN film is eroded, expose the p-GaN film, form table top;

4) on the table top of p-GaN film, make p1 type electrode;

5) manufacturing n type electrode on ZnO film.

Wherein substrate is Al ₂O ₃Material.

Wherein the hole concentration of p-GaN film is 10 ¹⁷-10 ¹⁹/ cm ³, hole mobility is 10-100cm ²/ Vs.

Wherein the depositing temperature of ZnO film is 300-900 ℃, and working gas is Ar, and pressure is 1.0Pa, and growth power is 80W, and sedimentation time is 10-60min, and the thickness of ZnO film is 100-2000nm.

Wherein the electron concentration of ZnO film is 10 ¹⁷-10 ¹⁹/ cm ³, electron mobility is 5-10000ccmm ²/ Vs.

Wherein the material of p type electrode is NiAu, and n type electrode 50 is the TiAu alloy.

The present invention also provides a kind of method of making zno-based heterojunction light-emitting diode, comprises the steps:

1) deposition p-GaN film on substrate;

2) growing AIN layer on the p-GaN film;

3) growing ZnO thin-film on the p-GaN film;

4) adopt wet etching, a side of the AlN layer on the p-GaN film and ZnO film is eroded, expose the p-GaN film, the formation table top;

5) on the table top of p-GaN film, make p type electrode;

6) manufacturing n type electrode on ZnO film.

Wherein substrate is Al ₂O ₃Material.

Wherein the hole concentration of p-GaN film is 10 ¹⁷-10 ¹⁹/ cm ³, hole mobility is 10-10000ccmm ²/ Vs.

Wherein the electron concentration of ZnO film is 10 ¹⁷-10 ¹⁹/ cm ³, electron mobility is 5-100cm ²/ Vs.

Wherein the material of p type electrode is NiAu, and the type electrode is the TiAu alloy.

Wherein the temperature of depositing Al N layer is 400-1000 ℃, and working gas is the mist of Ar and N2, and pressure is 1.0Pa in the growth room, and long power is 80W, and sedimentation time is 5-12min.

Wherein the thickness of AlN layer is 5-50nm.

Description of drawings

For further specifying characteristic of the present invention and technical scheme, below in conjunction with application example the present invention is explained in detail, wherein:

Figure 1A is a first embodiment of the invention n-ZnO/p-GaN heterojunction light-emitting diode structure sketch map.

Figure 1B is a second embodiment of the invention n-ZnO/AlN/p-GaN heterojunction light-emitting diode structure sketch map.

Fig. 2 is X-ray diffraction (XRD) spectrum according to the AlN film of embodiment of the invention preparation.

Fig. 3 is room temperature electroluminescent (EL) spectrum according to the n-ZnO/p-GaN heterojunction light-emitting diode of embodiment of the invention preparation.

Fig. 4 is room temperature electroluminescent (EL) spectrum according to the n-ZnO/AlN/p-GaN heterojunction light-emitting diode of embodiment of the invention preparation.

Embodiment

See also shown in Fig. 1 (A), be first embodiment of the invention, the present invention provides a kind of method of making zno-based heterojunction light-emitting diode, comprises the steps:

1) deposition p-GaN film 20 on substrate 10, this substrate 10 is Al ₂O ₃Material, the hole concentration of p-GaN film 20 are 10 ¹⁷-10 ¹⁹/ cm ³, hole mobility is 10-100cm ²/ Vs;

2) growing ZnO thin-film 30 on p-GaN film 20, used growth apparatus is the rf magnetron sputtering system, comprises Sample Room, settling chamber, vacuum system, radio-frequency power supply and matching system, substrate heating and temperature-controlling system, sample rotary system etc.;

3) make sputtering target with the ZnO ceramic target, target is packed on the radio frequency target platform in the growth room, and the distance of adjustment target and substrate is 80mm;

4) depositing temperature of this ZnO film 30 is 300-900 ℃, and working gas is Ar, and pressure is 1.0Pa, and growth power is 80W, and sedimentation time is 10-60min, and the thickness of ZnO film 30 is 100-2000nm, and electron concentration is 10 ¹⁷-10 ¹⁹/ cm ³, electron mobility is 5-100cm ²/ Vs;

5) adopt wet etching, a side of the ZnO film on the p-GaN film 20 30 is eroded, expose p-GaN film 20, form table top 21;

6) on the table top 21 of p-GaN film 20, make p type electrode 40, the material of this p type electrode 40 is NiAu;

7) manufacturing n type electrode 50 on ZnO film 30, this n type electrode 50 is the TiAu alloy.

Consult shown in Fig. 1 (B), be second embodiment of the invention, a kind of method of making zno-based heterojunction light-emitting diode of the present invention comprises the steps:

2) growing AIN layer 22 on p-GaN film 20, used growth apparatus is the rf magnetron sputtering system, comprises Sample Room, settling chamber, vacuum system, radio-frequency power supply and matching system, substrate heating and temperature-controlling system, sample rotary system etc.;

3) growing AIN layer 22 used working gas are the mist of Ar and N2, and ratio is 1: 1, and pressure is 1.0Pa in the growth room, and radio frequency sputtering power is 80W, and underlayer temperature is 750 ℃, and sputtering time is 12min, and growing period sample holder rotation makes film forming even.

4) growing ZnO thin-film 30 on p-GaN film 20, used growth apparatus is the rf magnetron sputtering system, the depositing temperature of this ZnO film 30 is 300-900 ℃; Working gas is Ar; Pressure is 1.0Pa, and growth power is 80W, and sedimentation time is 10-60min; The thickness of ZnO film 30 is 100-2000nm, and electron concentration is 10 ¹⁷-10 ¹⁹/ cm ³, electron mobility is 5-100cm ²/ Vs;

5) adopt wet etching, a side of AlN layer on the p-GaN film 20 22 and ZnO film 30 is eroded, expose p-GaN film 20, form table top 21;

6) on the table top 21 of p-GaN film 20, make p type electrode 40, the material of p type electrode 40 is the NiAu alloy, manufacturing n type electrode 50 on ZnO film 30, and n type electrode 50 is the TiAu alloy.

Growth result

According to above-mentioned process conditions, preparation n-ZnO/AlN/p-GaN sandwich structure device on GaN (0001) substrate, and under identical experiment condition, prepare simple n-ZnO/p-GaN device as comparing (as shown in Figure 1).The XRD result of the AlN that grows on the p-GaN/ Sapphire Substrate (Fig. 2) shows except GaN and sapphire diffraction maximum; Two peaks that have only 36.1o and 76.6o place; Owing to AlN (0002) and (0004) diffraction maximum, the crystalline quality of this explanation AlN better and along [0002] direction is grown respectively.Electroluminescence spectrum test (Fig. 3; Even Fig. 4) show conventional n-ZnO/p-GaN light-emitting diode under the big injection current luminous still a little less than; Show that the heterojunction device near interface defective that we prepare is a lot, injected electrons and hole are most of compound through non-radiative recombination center.Insert after the AlN intermediate layer,, luminously still obtained great enhancing even under less injection current, and the luminous good restraining that obtained that causes by fault in material in the device.

Invention is compared the significative results that is had with background technology

The luminous efficiency of conventional ZnO/GaN heterojunction light-emitting diode is very low; And with defect luminescence is main; The present invention is through inserting the thin AlN intermediate layer of one deck between ZnO and GaN; AlN and ZnO, the same wurtzite structure that is all of GaN, and lattice constant is very approaching, can guarantee the epitaxial quality of material.AlN is inserted with two clear superiorities: (1) AlN has good chemical stability; Can effectively suppress the counterdiffusion of the n-ZnO/p-GaN heterojunction boundary O of place atom and N atom; Reduce the formation of near interface non-radiative recombination center, improve the crystal mass of heterojunction boundary; (2) energy gap (6.2eV) that AlN is big can improve the potential barrier in heterojunction boundary electronics and hole, and electronics and hole are played good restriction, thereby improves the concentration near interface electronics and hole, improves the recombination rate in electronics and hole.Through inserting the AlN layer, can effectively solve the existing problem of n-ZnO/p-GaN light-emitting diode, thereby improve the device luminous efficiency greatly.

The above; Be merely the embodiment among the present invention, but protection scope of the present invention is not limited thereto, anyly is familiar with this technological people in the technical scope that the present invention disclosed; The conversion that can expect easily or replacement all should be encompassed in of the present invention comprising within the scope.Therefore, protection scope of the present invention should be as the criterion with the protection range of claims.

Claims

1. a method of making zno-based heterojunction light-emitting diode comprises the steps:

1) deposition p-GaN film on substrate;

2) growing AIN layer on the p-GaN film;

3) growing ZnO thin-film on the p-GaN film;

5) on the table top of p-GaN film, make p type electrode;

6) manufacturing n type electrode on ZnO film.

2. the method for making zno-based heterojunction light-emitting diode according to claim 1, wherein substrate is Al ₂O ₃Material.

3. the method for making zno-based heterojunction light-emitting diode according to claim 1, wherein the hole concentration of p-GaN film is 10 ¹⁷-10 ¹⁹/ cm ³, hole mobility is 10-100cm ²/ Vs.

4. the method for making zno-based heterojunction light-emitting diode according to claim 1, wherein the depositing temperature of ZnO film is 300-900 ℃, working gas is Ar; Pressure is 1.0Pa; Growth power is 80W, and sedimentation time is 10-60min, and the thickness of ZnO film is 100-2000nm.

5. the method for making zno-based heterojunction light-emitting diode according to claim 1, wherein the electron concentration of ZnO film is 10 ¹⁷-10 ¹⁹/ cm ³, electron mobility is 5-100cm ²/ Vs.

6. the method for making zno-based heterojunction light-emitting diode according to claim 1, wherein the temperature of depositing Al N layer is 400-1000 ℃, working gas is Ar and N ₂Mist, pressure is 1.0Pa in the growth room, growth power is 80W, sedimentation time is 5-12min.

7. the method for making zno-based heterojunction light-emitting diode according to claim 1, wherein the thickness of AlN layer is 5-50nm.