CN101055843A - Method for growing the ZnO thin film at the SiO2 underlay - Google Patents

Abstract

The invention discloses a method for growing a ZnO thin film on a SiO2 substrate, belongs to a semiconducor material and device field, especially is a method for growing a ZnO thin film on a SiO2 (quartz) substrate by an MBE. The method comprises steps of: a step 1, transmitting a cleaned SiO2 substrate into an MBE growing system, high-temperature treating 20-40 minutes under 700-900 DEG C, then oxygen-plasma treating 20-40 minutes under 400-500 DEG C; a step 2, growing an MgO flexible layer with a thickness of 1-4 nm under 400-500 DEG C; a step 3, annealing 10-30 minutes under 700-800 DEG C; a step 4, growing a ZnO transition layer with a thickness of 10-30 nm under 350-450 DEG C; a step 5, annealing 10-30 minutes under 700-800 DEG C and an oxygen-plasma atmosphere; a step 6, extension growing the ZnO thin film under 600-700 DEG C. In the method of replacing sapphire by SiO2 and growing a high-quality ZnO thin film on a substrate of silicon or the like, the high-quality ZnO thin film is prepared by the MgO flexible layer and the ZnO transition layer. Advantages of the SiO2 substrate is simple preparing process, low cost, and good for application in photoelectron devices.

Description

At SiO 2The method of growing ZnO thin-film on the substrate

Technical field

The invention belongs to semi-conducting material and devices field, relate to the method for a kind of growth wide bandgap semiconductor zinc oxide (ZnO) monocrystal thin films, particularly at quartzy (SiO ₂) on the substrate with the method for molecular beam epitaxy (MBE, P-MBE, RF-MBE, L-MBE) developing ZnO monocrystal film.

Background technology

ZnO is a kind of direct band semiconductor, have wide band gap (room temperature 3.37eV), big exciton binding energy (60meV) and strong lot of advantages such as light emission, at the desirable candidate material of opto-electronic devices such as transparency electrode, detector, transducer, surface acoustic wave filter, solar cell, short wavelength laser and light-emitting diode.It is the direct carrying semiconductor material in another important broad stopband behind gallium nitride (GaN).Aspect the short-wavelength light electronic device of low, the low-loss of preparation threshold value, high efficiency and hot operation very application prospects is being arranged.Yet high quality ZnO film is the basis of realizing its device.Though ZnO single crystalline substrate commercialization at present, large-sized substrate are difficult to obtain, its price is also very expensive, so the isoepitaxial growth technology of ZnO monocrystal thin films also can't extensive use.ZnO film is still mainly grown on sapphire (0001) substrate at present.Because ZnO and sapphire lattice mismatch big (18%) cause high problems such as defect concentration easily.Therefore suitable epitaxially grown substrate of ZnO monocrystal thin films of exploration and corresponding high-quality thin film growing technology have crucial meaning.

Summary of the invention

Technical problem to be solved by this invention is to provide a kind of at SiO ₂The method of growing ZnO thin-film on the substrate, this method is passed through SiO ₂The surface preparation of substrate, MgO flexible layer, ZnO transition zone and high annealing grow high-quality ZnO film.

Technical scheme of the present invention:

At SiO ₂The steps in sequence of the method for growing ZnO thin-film is on the substrate:

Step 1 is with the SiO that cleaned ₂Substrate imports the MBE growing system into, under 700-900 ℃, and high-temperature process 20-40 minute, again under 400-500 ℃, oxygen plasma treatment 20-40 minute;

Step 2, under 400-500 ℃, growth thickness is the MgO flexible layer of 1-4nm;

Step 3, under 700-800 ℃, annealing in process 10-30 minute;

Step 4, under 350-450 ℃, growth thickness is the ZnO transition zone of 10-30nm;

Step 5, under 700-900 ℃, annealing is 10-30 minute under the oxygen plasma atmosphere;

Step 6 under 600-700 ℃, is carried out the epitaxial growth of ZnO film.

Beneficial effect of the present invention:

Use SiO ₂Replace the method for substrate growing high-quality ZnO films such as sapphire and silicon, prepare high-quality ZnO film by MgO flexible layer and ZnO transition zone.SiO ₂The advantage of substrate is that preparation technology is simple, cost is low, helps the application aspect opto-electronic device.

Description of drawings

Fig. 1 is at SiO ₂The room temperature photoluminescence spectra of growing ZnO thin-film on the substrate.

Fig. 2 is at SiO ₂The XRD figure of growing ZnO thin-film on the substrate.

Embodiment

At SiO ₂The method of growing ZnO thin-film on the substrate, the steps in sequence of its execution mode one is:

Step 1 is with the SiO that cleaned ₂Substrate imports the MBE growing system into, under 800 ℃, and high-temperature process 30 minutes, again under 450 ℃, oxygen plasma treatment 25 minutes;

Step 2, under 450 ℃, growth thickness is the MgO flexible layer of 1-2nm;

Step 3, under 750 ℃, annealing in process 10 minutes;

Step 4, under 400 ℃, growth thickness is the ZnO transition zone of 20nm;

Step 5, under 750 ℃, annealing is 10 minutes under the oxygen plasma atmosphere;

Step 6 under 650 ℃, is carried out the epitaxial growth of ZnO film.

The steps in sequence of execution mode two is:

Step 1 is with the SiO that cleaned ₂Substrate imports the MBE growing system into, under 700 ℃, and high-temperature process 20 minutes, again under 400 ℃, oxygen plasma treatment 20 minutes;

Step 2, under 400 ℃, growth thickness is the MgO flexible layer of 1-2nm;

Step 3, under 700 ℃, annealing in process 10 minutes;

Step 4, under 350 ℃, growth thickness is the ZnO transition zone of 10nm;

Step 5, under 700 ℃, annealing is 10 minutes under the oxygen plasma atmosphere;

Step 6 under 600 ℃, is carried out the epitaxial growth of ZnO film.

The steps in sequence of execution mode three is:

Step 1 is with the SiO that cleaned ₂Substrate imports the MBE growing system into, under 850 ℃, and high-temperature process 40 minutes, again under 480 ℃, oxygen plasma treatment 30 minutes;

Step 2, under 480 ℃, growth thickness is the MgO flexible layer of 3-4nm;

Step 3, under 780 ℃, annealing in process 20 minutes;

Step 4, under 450 ℃, growth thickness is the ZnO transition zone of 30nm:

Step 5, under 850 ℃, annealing is 30 minutes under the oxygen plasma atmosphere;

Step 6 under 680 ℃, is carried out the epitaxial growth of ZnO film.

The process of pressing above-mentioned execution mode one is at SiO ₂The ZnO film for preparing on the substrate, at room temperature record photoluminescence spectra as shown in Figure 1, as seen from Figure 1, only observe the ultra-violet light-emitting of free exciton, and it is luminous not observe the deep energy level relevant with defective, shows that ZnO film has higher quality and low defect concentration.And the structure of this film studied, the XRD spectrum that records ZnO film can be observed one by Fig. 2 and be positioned at 34.59 ° of very strong diffraction maximums as shown in Figure 2, and it originates from (0002) diffraction of ZnO, and another is positioned at 21.7 ° of more weak diffraction maximums is SiO ₂Diffraction.In Fig. 2, do not observe the diffraction maximum in other crystal orientation of ZnO, show that the ZnO film that the present invention prepares has the well preferred orientation in (0002) crystal orientation, promptly along wurtzite structure c axle oriented growth.

Use SiO ₂Replace the grow tall method of quality ZnO film of substrate dirt such as sapphire and silicon, flexible and ZnO transition zone is prepared high-quality ZnO film by MgO.SiO ₂The advantage of substrate is that preparation technology is simple, cost is very low, helps the application aspect opto-electronic device.

Claims (1)

1. at SiO ₂The method of growing ZnO thin-film is characterized in that on the substrate, and the steps in sequence of this method is:

Step 1 is with the SiO that cleaned ₂Substrate imports the MBE growing system into, under 700-900 ℃, and high-temperature process 20-40 minute, again under 400-500 ℃, oxygen plasma treatment 20-40 minute;

Step 2, under 400-500 ℃, growth thickness is the MgO flexible layer of 1-4nm;

Step 3, under 700-800 ℃, annealing in process 10-30 minute;

Step 4, under 350-450 ℃, growth thickness is the ZnO transition zone of 10-30nm;

Step 5, under 700-900 ℃, annealing is 10-30 minute under the oxygen plasma atmosphere;

Step 6 under 600-700 ℃, is carried out the epitaxial growth of ZnO film.

Images