ZnGaO Ultraviolet detector and preparation method thereof

Mode of execution

The ZnGaO ultraviolet detector, comprises a substrate, a zinc-gallium-oxygen material film, a metal interdigital electrode and an indium electrode; which are sequentially compounded.

The atomic ratio of zinc and gallium in the zinc-gallium-oxygen material film is more than 1:2, and the zinc-gallium-oxygen material film is a spinel structure.

To 1, FIG. 1 is a structural schematic ZnGaO of. ultraviolet detector.

The ultraviolet detector comprises the substrate, the substrate is a substrate known to a person skilled in the art, is not particularly limited, and the sapphire substrate, magnesium oxide or magnesium aluminate. is preferably used in the present invention.

The ultraviolet detector provided by the invention further comprises a zinc-gallium-oxygen material film. which is compounded on the substrate.

The atomic ratio of zinc and gallium in the zinc-gallium-oxygen material film is more than 1:2, and the zinc-gallium-oxygen material film is a spinel structure.

In the present invention, the chemical formula of the zinc-gallium-oxygen material film is Zn._x Ga_y O₄ , x:y ＞ 1:2, May also depend on the unitz-type. 1:1.6 ≥ x:y ＞ 1:2

In some embodiments of the present invention, the atomic ratio of zinc to gallium is 1:1.7, 1:1.92, 1:1.88, 1:1.65, 1:1.6, 1:1.98, 1:1.9 or 1:1.62.

The crystalline phase of the zinc-gallium-oxygen film is ZnGa.₂ O₄ The structure, light-absorbing cut-off edge is located 250 ± 10nm, and the absorption edge is very steep.

It is possible to prepare a thin film, having a large area having an area (0.1-6)cm × (0.1-6)cm whose light absorption property and crystal structure are uniformly. in all ranges.

The preparation method, of the zinc-gallium-oxygen material film comprises the following steps :

An organic zinc compound is used as a zinc source, organic gallium compound as a gallium source, and a zinc-gallium-oxygen material film, is grown on the surface of a substrate with high purity oxygen as an oxygen source. using a metal organic compound chemical vapor deposition method.

In the present invention, the atomic ratio of zinc to gallium in the zinc-gallium-oxide-material film can be more than 1:2. in three ways.

(1) Gradually reducing carrier gas flow; of gallium source during growth process

(2) Gradual rise growth process zinc source's carrier gas flow.

(3) Gradually decreasing the growth temperature.

In the above three ways, one of the modes, may be used alone, or any two or more combinations. may be used in any of three ways.

A specific, method for cleaning a substrate, before metal organic chemical vapor deposition is performed, is :

The substrate, is washed successively with trichloroethylene, acetone and ethanol and then dried. with dry nitrogen.

The substrate is sapphire, magnesium oxide, zinc oxide or magnesium aluminate, is preferably sapphire.

, The substrate was then placed in MOCVD growth apparatus, to adjust the growth starting temperature to 500-800 °C, wherein the vacuum degree of the growth chamber in, growth apparatus was 2*10.² -1*10⁴ Pa, Is preferably 8 × 10.² -5 × 10³ Pa.

The organic zinc compound is diethyl zinc and/or dimethylzinc; and the organic gallium compound is trimethyl gallium and/or triethylgallium.

The molar concentration of zinc and gallium was adjusted. using a different ratio of high purity nitrogen gas.

The organic zinc compound has a starting flow rate, of carrier gas 5-20mL/min, of 10-15mL/min, preferably, at a rate of, ° C. for 0-4.5mL/30min, hours 0.5-4mL/30min, and preferably 1-3mL/30min; hours 0-5 and more preferably, hour 1-5 in the growth of the zinc-gallium oxide film during the growth of the zinc-gallium-oxygen material film, 2-4 .

The initial flow rate of the carrier gas, is 5-40mL/min, preferably 10-35mL/min, more preferably 15-30mL/min, at a rate of, preferably, and preferably 0-4.5mL/30min, hours 0.5-4mL/30min, more preferably 1-3mL/30min; hours 0-5, and further preferably, hours 1-5 in the growth of the zinc-gallium-oxide film during the growth of the zinc-gallium-oxygen material film, during the growth 2-4 of. the zinc-gallium-oxide film.

The flow rate of the oxygen is 100-1000mL/min.

The growth time, during film growth is 0.5-5h, preferably 1-4h, and the growth starting temperature is 500-800 °C, preferably 600-700 °C.

In growing the zinc-gallium-oxygen material film, the growth temperature 0.01-5 °C/min is gradually decreased at a cooling rate, the cooling rate is 0.05-5 °C/min, more preferably 0.1-3 °C/min; the cooling time 0.5-5h, is ≤, and the growth time. may be continuously, or continuously, in the process. of the present invention.

After the growth is finished, the temperature of the substrate to room temperature, is decreased, and the cooling rate is 0.1-50 °C/min. in the present invention, and the room temperature is defined 25 ± 5 °C.

The thickness of the zinc-gallium-oxygen-material film is 100-600nm, and 200-500nm, is more preferably 300-400nm.

Next, a substrate with a zinc-gallium-oxygen material film is placed in the vacuum coating machine, and the interdigital electrode mask, is formed by using negative resist lithography.

The specific, is 1 × 10 at atmospheric pressure.^-3 -1 × 10^-2 Pa Uses the evaporation current, to deposit 10-140A, metal particles onto the zinc-gallium-oxide-material film surface 5-500mg and metal-metal-finger electrodes, are preferably metal interdigital electrodes. in the present invention by photolithography and a wet etching surface metal .

In the present invention, the finger pitch of the metal interdigital electrode is 2-10 μ m, fingers, the length of 10-25 pairs, fingers is 0.5-2mm, fingers, and the width is 2-10 μ m.

Finally, presses In particles on the metal interdigital electrode to obtain MSM ultraviolet detector ZnGaO of. structure.

The performance characterization method of the zinc-gallium-oxygen ultraviolet detector uses :ray diffraction X to characterize the crystal structure (XRD) to characterize the element ratio. of the material using the ultraviolet (EDS) visible light absorption spectroscopy instrument test material. to acquire the dark current data - and the optical switch curve, from. curve IV of the semiconductor analyzer measuring device to obtain) response time data). ((.

For further understanding, the ZnGaO ultraviolet detector and the preparation method thereof according to the present invention will be described, and the protection scope of the present invention is not limited. by the following examples.

Embodiment 1:

Preparation process ZnMgO of short wave: ultraviolet detector

(1) The sapphire substrate, was cleaned separately using trichloroethylene, acetone, ethanol and then dried. with dry nitrogen.

(2) Places the sapphire substrate in step (1) into MOCVD growth apparatus, starting growth temperature 730 °C, growth chamber vacuum 1.2*10.³ Pa, Uses diethylzinc as the zinc source, trimethyl gallium as the gallium source, zinc and gallium to adjust, the carrier gas flow rate of 230mL/min, trimethyl gallium pipeline to 10mL/min, increasing the carrier gas flow 30mL/min. for, hours. to increase the carrier gas flow rate for 1mL/30min. hours during growth of 1 hours at a rate. decreasing the growth temperature, gradually during the growing process. hours at the growth process 3 °C/min, 1.

(3) Hours 3 of growth, hours to turn off organic source, at 5 °C/min rate decrease temperature, eventually to room temperature, taking out substrate, to obtain a substrate, covered with a thin film of zinc gallium oxide material having an area 2cm*5cm.

(4) The sample in step (3) was placed in a vacuum coater, at a gas pressure 1*10.^-3 Pa Particles were evaporated to the sample surface, using the evaporation current 140A, under 50mg Au. conditions.

(5) The sample obtained in step (4) is pressed, on the interdigital electrode by gold from the surface of the photolithography and wet etching to obtain In structure of MSM ultraviolet detector ZnGaO, the finger pitch of. prong is that the length of 2 μ m, prong and the width 25 2mm, prong are 2 μ m, fingers.

[X] The,ray diffraction 2, spectrogram 2 of a film coated with a zinc-gallium-oxygen material as a result of X-ray diffraction (XRD) in FIG. shows, and it can be seen from the figure that the material is ZnGa.₂ O₄ The absorption peak of the crystal phase structure .XRD is sharp, and the crystallization quality is higher.

3 Is a graph 1 of the photoelectron spectrum ZnGaO of (EDS) film in Example, from the graph that the ratio of, zinc element to gallium element is about 1:1.7. and the standard ZnGa.₂ O₄ The ratio 1:2 of the thin film zinc and gallium was less, than. Ga atoms.

4 Is a ZnGaO nm ultraviolet - visible light absorption spectrum, and it can be seen that the thin film has a steep single light absorption cutoff edge, light absorption cutoff edge of about 250nm Å.

Comparative Example 1

Compared 1 with Example, the process, of gradually increasing the carrier gas flow rate, of the zinc source during growth, i.e. maintaining the zinc source initial carrier gas flow rate, while eliminating the growth temperature, gradually decreasing the growth temperature, does not change, to obtain a corresponding. device 730 °C. in which the zinc-gallium-oxygen material film has a zinc and gallium atomic ratio 1:2.

Example 1 and Comparative Example 1 The results of performance measurement, are shown 5-7. and 5- and FIG. 7 shows that the response time of, device responsiveness, of FIG. (and the dark current 5) of FIG. (significantly shortens 6) as shown in FIG. with respect to the reduction (device responsivity of gallium in the 7). ratio of zinc and gallium atoms.

5 Shows that the peak responsiveness of the device of Example, is 1, and the peak responsiveness of the device provided in Comparative Example 9.4A/W, is 1 9.8A/W.

6 Shows that the device of Example, when the voltage was 1, the dark current of 10V versus Comparative Example 1.8nA, was 1 when the voltage was 10V 1.8nA.

As shown 7 in the, embodiment 1, the time required to turn, current down to one thousandth of the original state after the device turns off light is about 80 ms, to the device 1 of Comparative Example, at a time required to turn 500 from. ms 1 to the device of Example 1 at a time of about. one thousandth of the original state.

Embodiment 2

Compared 1 to Example, only changing the rate, of increase of the zinc source carrier gas flow does not alter the other conditions to prepare a batch of sample. sample numbers 2-1,2-2,2-3,2-4,2-5 with a rate of increase 0.1mL/30min;0.5mL/30min;2mL/30min;3mL/30min;5mL/30min. of the zinc source carrier gas flow rate.

The results are: respectively.

The sample obtained 2-1,2-2,2-3,2-4 samples had a material of ZnGa.₂ O₄ The crystal phase structure, has a light absorption cutoff edge of about 250nm Å. Å.

The sample obtained from 2-5 samples had a small ZnO crystal structure, with two absorption cut-off edges.

The sample of 2-1,2-2,2-3,2-4,2-5 has a sample zinc element and a gallium element in a ratio of about 1/1.92,1/1.88,1/1.65,1/1.6,1/1.5.

EXAMPLE 2 The peak responsivity, of the device prepared in Example CE was tested 10V as a result of the dark current when the voltage was, and the time required to turn off, current after the device was 1. turned off to one thousandth of the original state.

Table 1 device performance measurement results

Embodiment 3

Compared 1 to Example, the cooling rate, of the sample No. of the batch of samples 3-1,3-2,3-3,3-4,3-5 was prepared 0.01 °C/min,1 °C/min,5 °C/min,6 °C/min,7 °C/min only by changing the cooling rate at the production process without changing the other conditions.

The results are: respectively.

The sample obtained 3-1,3-2,3-3 samples had a material of ZnGa.₂ O₄ The crystal phase structure, has a light absorption cutoff edge of about 250nm Å. Å.

The sample obtained from 3-4,3-5 samples had a small ZnO crystal structure, with two absorption cut-off edges.

The sample of 3-1,3-2,3-3,3-4,3-5 has a sample zinc element and a gallium element in a ratio of about 1/1.98,1/1.9,1/1.62,1/1.58,1/1.5.

EXAMPLE 3 The peak responsivity, of the device prepared in Example CE was tested 10V as a result of the dark current when the voltage was, and the time required to turn off, current after the device was 2. turned off to one thousandth of the original state.

Table 2 device performance measurement results

It should be noted that, is only a preferred embodiment, of the present invention, and it should be pointed out that those skilled in the art, without departing from the principles of the invention, also make several improvements and modifications, which should also be considered as protection scope. of the present invention.