CN111710591A - A kind of Ga2O3 film and preparation method thereof - Google Patents

Abstract

The invention provides Ga₂O₃The preparation method of the film comprises the following steps: taking an organic gallium compound as a gallium source, taking high-purity oxygen as an oxygen source, depositing on the surface of a substrate by a metal organic chemical vapor deposition method, and cooling to obtain Ga₂O₃A film; in Ga₂O₃And intermittently supplementing the organic magnesium compound in the process of growing the film. The application also provides Ga prepared by the preparation method₂O₃Film of Ga₂O₃The film is doped with trace magnesium. The present application relates to the preparation of Ga₂O₃The access time and the access time of the organic magnesium compound in the film are controlled, and the trace magnesium-doped Ga is realized₂O₃Preparation of thin film for realizing high-performance solar-blind ultraviolet light detectorProvides a convenient and effective means.

Description

A kind of Ga2O3 film and preparation method thereof

technical field

The invention relates to the technical field of semiconductors, in particular to a Ga ₂ O ₃ thin film and a preparation method thereof.

Background technique

Ultraviolet detection technology is another new type of dual-use detection technology developed after laser and infrared detection technology. It currently plays a huge role in many fields such as missile tail flame detection, space detection, flame detection and space communication. Especially for detectors working in the solar-blind band (200-280nm), the sensitivity is greatly improved due to the absence of solar ultraviolet interference. In recent years, wide-bandgap semiconductor UV detectors are considered to be the third-generation UV detectors that can replace vacuum photomultiplier tubes and Si photomultiplier tubes due to their small size, light weight, and no need for filters and refrigeration. device.

Ga ₂ O ₃ is a new type of direct band gap wide band gap semiconductor with a band gap of about 4.9 eV at room temperature. Because of its large band gap, the absorption edge is located in the solar-blind band, which is a natural preparation for solar-blind. Materials for UV detectors. However, the comprehensive performance of the current UV detectors based on Ga ₂ O ₃ materials is still relatively low, especially the response time of devices with higher responsivity is often longer. Practice has shown that a very small amount of impurities can change its performance, but there is little related research work at present, and how to use an appropriate doping method to greatly improve the comprehensive performance of the device remains to be studied.

SUMMARY OF THE INVENTION

The technical problem solved by the present invention is to provide a Ga ₂ O ₃ thin film and a preparation method thereof. The preparation method of the Ga ₂ O ₃ thin film provided by the present application realizes the preparation of the Ga ₂ O ₃ thin film of high quality and trace doped magnesium element. The thin film applied to the ultraviolet detector has high ultraviolet light responsivity and short response time.

In view of this, the present application provides a preparation method of Ga ₂ O ₃ thin film, comprising the following steps:

The organic gallium compound is used as the gallium source, the high-purity oxygen is used as the oxygen source, the metal organic chemical vapor deposition method is used to deposit on the surface of the substrate, and the Ga ₂ O ₃ film is obtained after cooling down;

During the growth of the Ga ₂ O ₃ film, the organomagnesium compound is intermittently supplemented, and the time for supplementing the organomagnesium compound starts 0.1-6 h after the Ga ₂ O ₃ film starts growing, and ends 0.1-6 h before the Ga ₂ O ₃ film stops growing. 6h;

The specific method of intermittently replenishing the organomagnesium compound is to turn on the organomagnesium compound for 10s-600s, and turn off the organomagnesium compound for 10s-600s, and repeat 1-1000 times.

Preferably, the organic gallium compound uses high-purity nitrogen as the carrier gas, and the flow rate of the carrier gas is 10-40 sccm; the flow rate of the high-purity oxygen is 100-400 sccm; the organic magnesium compound uses high-purity nitrogen as the carrier. , the flow rate of the carrier is 1-20 sccm.

Preferably, the organogallium compound is selected from one or both of trimethylgallium and triethylgallium, and the organomagnesium compound is selected from one or both of dicocene and dimethylmagnesene kind.

Preferably, the deposition temperature is 400˜1100° C., the deposition time is 1 h˜6 h, and the vacuum degree of the deposition is 5×10 ^2˜1 ×10 ⁴ Pa.

Preferably, the substrate is selected from sapphire substrate, magnesium oxide or magnesium aluminate.

Preferably, the cooling rate is 0.2-0.8°C/s.

Preferably, the time for supplementing the organomagnesium compound starts 0.3-0.7 h after the Ga ₂ O ₃ film starts growing, and ends 0.3-0.7 h before the Ga ₂ O ₃ film stops growing.

Preferably, the specific method of intermittently replenishing the organic magnesium compound is to turn on the organic magnesium compound for 30s to 160s, close it for 30s to 160s, and repeat 10 to 100 times.

The present application also provides the Ga _{2 O 3 thin film prepared by the preparation method, and the Ga 2 O 3 thin film} is doped with a trace amount of magnesium.

Preferably, the magnesium content cannot be detected by EDS test.

The present application provides a method for preparing a Ga ₂ O ₃ thin film, which uses an organic gallium compound as a gallium source and high-purity oxygen as an oxygen source, and uses a metal organic chemical vapor deposition method to deposit on the surface of the substrate. Ga ₂ O ₃ thin films are obtained; and in the process of film growth, by introducing organomagnesium compounds, and controlling the introduction time and opening mode of organomagnesium compounds, the Ga ₂ O ₃ films are doped with trace magnesium elements, and the doping of magnesium The amount is a small amount, so that the film has a short response time for ultraviolet detection.

Description of drawings

Fig. 1 is the X-ray diffraction spectrum of the Ga ₂ O ₃ film obtained in the embodiment of the present invention 1;

Fig. 2 is the ultraviolet-visible light absorption spectrogram of the Ga ₂ O ₃ film obtained in Example 1 of the present invention;

Fig. 3 is the X-ray energy spectrum analysis spectrogram of the Ga ₂ O ₃ film obtained in Example 1 of the present invention;

4 is a current-time characteristic curve of the Ga ₂ O ₃ thin film obtained in Example 1 of the present invention.

Detailed ways

In order to further understand the present invention, the preferred embodiments of the present invention are described below in conjunction with the examples, but it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, rather than limiting the claims of the present invention.

The present application provides a method for preparing a Ga ₂ O ₃ thin film. The Ga ₂ O ₃ thin film is doped with a trace amount of magnesium by using a metal organic compound chemical vapor deposition method, so that the thin film is applied to an ultraviolet detector and has High UV responsivity and short response time. Specifically, the embodiment of the present invention discloses a method for preparing a Ga ₂ O ₃ film, which includes the following steps:

The organic gallium compound is used as the gallium source, the high-purity oxygen is used as the oxygen source, the metal organic chemical vapor deposition method is used to deposit on the surface of the substrate, and the Ga ₂ O ₃ film is obtained after cooling down;

During the growth of the Ga ₂ O ₃ film, the organomagnesium compound is intermittently supplemented, and the time for supplementing the organomagnesium compound starts 0.1-6 h after the Ga ₂ O ₃ film starts growing, and ends 0.1-6 h before the Ga ₂ O ₃ film stops growing. 6h;

The specific method of intermittently replenishing the organomagnesium compound is to turn on the organomagnesium compound for 10s-600s, and turn off the organomagnesium compound for 10s-600s, and repeat 1-1000 times.

The present application adopts the metal organic compound chemical vapor deposition method to prepare the Ga ₂ O ₃ thin film, that is, the preparation of the Ga ₂ O ₃ thin film is carried out in a heterometal organic compound chemical vapor deposition equipment; In the cavity of an organic compound chemical vapor phase device (MOCVD), the substrate may be a substrate well known to those skilled in the art. For example, the substrate may be selected from sapphire substrate, magnesium oxide or magnesium aluminate ; The substrate is preferably placed in the MOCVD equipment growth chamber after being cleaned and dried.

After the substrate is put into the cavity, the cavity is evacuated, and then the substrate is heated. This is the preparation work for the chemical vapor deposition of metal organic compounds. When the substrate is heated to the reaction temperature of deposition , the Ga ₂ O ₃ film can be deposited on the surface of the substrate.

In the process of preparing the Ga ₂ O ₃ thin film, the organic gallium compound is used as the gallium source, and the high-purity oxygen gas is used as the oxygen source, and the Ga ₂ O ₃ thin film is grown on the surface of the substrate. In this application, the organic gallium compound is selected from one or both of trimethylgallium and triethylgallium. In a specific embodiment, the organic gallium compound is selected from trimethylgallium; the organic gallium compound is selected from trimethylgallium. For the gallium compound, high-purity nitrogen is used as the carrier gas, and the flow rate of the carrier gas is 10-40 sccm. In a specific embodiment, the flow rate of the carrier is 20-30 sccm. The oxygen is used as an oxygen source, and its flow rate is 100-400 sccm, and in a specific embodiment, the flow rate is 200-300 sccm.

During the above deposition process, the organomagnesium compound is supplemented intermittently, and the time for supplementing the organomagnesium compound starts 0.1-6 hours after the Ga ₂ O ₃ film starts growing, and ends 0.1-6 hours before the Ga ₂ O ₃ film stops growing. A small amount of magnesium doping can be obtained in the final Ga ₂ O ₃ film, and the time for supplementing the organomagnesium compound starts from 0.3 to 0.7 hours after the Ga ₂ O ₃ film starts to grow, and ends 0.3 hours before the Ga ₂ O ₃ film stops growing. ~0.7h. Similarly, the opening time of the organomagnesium compound will also affect the doping of magnesium in the film. The specific method of intermittently replenishing the organomagnesium compound is to turn on the organomagnesium compound for 10s to 600s, close it for 10s to 600s, and repeat for 1 to 1000 times; In a specific embodiment, the specific method of intermittently replenishing the organomagnesium compound is to turn on the organomagnesium compound for 30s-160s, close for 30s-160s, and repeat 10-100 times. The organomagnesium compound is used as a magnesium source doped with trace magnesium in the present application, and it can be selected from one or both of dicocene and dimethylmagnesium, and the organomagnesium compound uses high-purity nitrogen as a carrier gas , its flow rate is 10-40 sccm, more specifically, the flow rate of the carrier gas is 2-5 sccm. In order to obtain a trace amount of magnesium doping, during the deposition process, the opening and closing timing and opening time of the above-mentioned organomagnesium compounds will have a great influence.

According to the present invention, in the whole deposition process, the deposition temperature is 400-1100°C, preferably 800-900°C; the deposition time is 1h-6h, preferably 1.5-2.5h; The degree of vacuum is 5×10 ² to 1×10 ⁴ Pa, preferably 8×10 ² to 5×10 ³ Pa.

The chemical vapor deposition of metal organic compounds described in this application is a chemical vapor deposition method well known to those skilled in the art, and the specific implementation process in this process is not particularly limited in this application, and can be performed according to a process well known to those skilled in the art.

After the deposition and growth is completed, the temperature of the substrate is lowered to room temperature to obtain a Ga ₂ O ₃ film, and the cooling rate is 0.2-0.8° C./s, preferably 0.4-0.6° C./s. In the present application, the temperature of the room temperature is specifically 25±5°C.

The present application also provides the Ga ₂ O ₃ thin film prepared by the above method, which is doped with a trace amount of magnesium. The trace amount of magnesium doped in this application cannot be detected in the EDS test, but according to the performance comparison, it is indeed due to the trace amount of magnesium doped, which makes the film used for ultraviolet detectors with high ultraviolet light responsivity and Very short response time.

The invention provides a Ga ₂ O ₃ thin film and a preparation method thereof, comprising the following steps: using an organic gallium compound as a gallium source, using high-purity oxygen as an oxygen source, and depositing Ga on the surface of a substrate by a metal organic compound chemical vapor deposition method ₂ O ₃ film. The preparation method of the Ga ₂ O ₃ thin film provided by the present invention utilizes the metal organic compound chemical vapor deposition (MOCVD) technology, the organic gallium compound is used as the gallium source, the high-purity oxygen is used as the oxygen source, and the growth temperature, the gallium source and the oxygen flow rate are determined by the growth temperature, the gallium source and the oxygen flow rate. The precise control of Ga2O3 and the addition of organomagnesium compounds as a magnesium source under specific conditions during the growth process enables the growth of _Ga2O3 thin films with micro _- doping of magnesium, which provides convenience for the realization of high-performance solar-blind UV photodetectors effective measures.

In order to further understand the present invention, the preparation method of the Ga ₂ O ₃ film provided by the present invention will be described in detail below with reference to the examples, and the protection scope of the present invention is not limited by the following examples.

Example 1

Put the cleaned sapphire substrate into the MOCVD growth chamber, turn on the molecular pump, and make the vacuum degree of the back of the chamber reach less than 100Pa; raise the substrate temperature to 1100°C, and after pretreatment for 0.5h, reduce the temperature to growth rate. The temperature is 800°C; nitrogen gas is introduced to make the vacuum degree of the cavity during the growth process to be 2×10 ³ Pa;

Trimethyl gallium was used as the gallium source, the carrier gas flow rate of the gallium source was 25 sccm, and the flow rate of oxygen was 250 sccm; during the growth process, dimethyldimethocene was used as the magnesium source, and the magnesium source was turned on after 0.2 h of growth, and the magnesium The carrier gas flow rate of the source is 4sccm, the magnesium source is turned on for 30s, closed for 120s, repeated twenty times, and then the addition of the magnesium source is stopped;

The whole growth process is 2h (including the time when the magnesium source is turned on intermittently). After the growth, the organic source and oxygen are turned off, and the substrate temperature is lowered to room temperature at 0.5°C/s to obtain a Ga ₂ O ₃ film.

The Ga ₂ O ₃ film obtained in Example 1 is subjected to powder X-ray diffraction (XRD) test, and its spectrum is shown in Figure 1. It can be seen from the figure that only the diffraction peak of Ga ₂ O ₃ and the absorption of XRD The peaks are sharper, indicating higher crystalline quality.

The Ga ₂ O ₃ film obtained in Example 1 was tested by ultraviolet-visible light absorption spectrum, and its spectrum was shown in Figure 2. It can be seen from the figure that the prepared Ga ₂ O ₃ film has a relatively steep single light absorption The cut-off edge, the light absorption cut-off edge, is around 250 nm.

EDS test was performed on the Ga ₂ O ₃ film obtained in Example 1, and its spectrum was obtained as shown in Figure 3. It can be seen from Figure 3 that only Ga, Al, O can be observed in the prepared Ga ₂ O ₃ film. element, no obvious magnesium element is found, and it should be noted that the Al element is derived from the substrate.

For the Ga ₂ O ₃ film obtained in Example 1, an ultraviolet detector was prepared by photoetching interdigitated gold electrodes, and a voltage of 10V was applied to both ends of the detector, and a current-time characteristic test was carried out using an ultraviolet lamp switch, The spectrum obtained is shown in Figure 4. It can be seen from the figure that the prepared Ga ₂ O ₃ film has a low dark current of about 10pA in the dark state, and a high photocurrent when irradiated by ultraviolet light, It can reach more than 60μA; when the ultraviolet light stops irradiating, it can quickly return to the dark current state, the response time of 90-10% is 60ms, and it only takes 1.07s to reduce to 0.1% of the highest photocurrent; it shows that the film has high UV light responsivity and very short response time.

Comparative example 1 is to verify the influence of micro-doping magnesium on film properties, except that no magnesium is doped, other conditions are the same as in Example 1, and the growth conditions are as follows:

Put the cleaned sapphire substrate into the MOCVD growth chamber, turn on the molecular pump, and make the vacuum degree of the back of the chamber reach less than 100Pa; raise the substrate temperature to 1100°C, and after pretreatment for 0.5h, reduce the temperature to growth rate. The temperature is 800°C; nitrogen gas is introduced to make the vacuum degree of the cavity during the growth process to be 2×10 ³ Pa;

Trimethylgallium was used as the gallium source, the carrier gas flow rate of the gallium source was 25 sccm, and the flow rate of oxygen was 250 sccm; after growth for 2 h, the organic source and oxygen were turned off, and the substrate temperature was lowered to room temperature at 0.5°C/s to obtain a Ga ₂ O ₃ film .

The Ga ₂ O ₃ film obtained in Comparative Example 1 was subjected to powder X-ray diffraction (XRD) test, UV-Vis absorption spectrum test and EDS test; the results were all consistent with the Ga ₂ O ₃ film obtained in Example 1: XRD It shows that the crystal quality is high; the absorption spectrum shows that the film has a steep single light absorption cut-off edge, and the light absorption cut-off edge is about 250nm; EDS can only observe Ga, Al, O elements.

For the Ga ₂ O ₃ film obtained in Comparative Example 1, an ultraviolet detector was prepared by photolithography with interdigitated gold electrodes. A voltage of 10V was applied to both ends of the detector, and a UV lamp switch was used to conduct a current-time characteristic test. The Ga ₂ O ₃ film has a low dark current of about 10pA in the dark state, and a high photocurrent of more than 30μA when irradiated with ultraviolet light.

The 90-10% response time is 500ms, and the time to reduce to 0.1% of the highest photocurrent is more than 5s; compared with Example 1, the response time is significantly longer, indicating that the magnesium element doped in Example 1, although there is no direct was detected, but still significantly improves the performance of the thin film, which can increase the photocurrent while reducing the response time.

Example 2

In order to verify the influence of the magnesium source start-up time on the film properties, other conditions were the same as those in Example 1 except that the magnesium source start-up time was changed. The start-up times of the samples numbered 2-1, 2-2, 2-3, and 2-4 were 0.1h, 0.5h, 0.8h, and 1h, respectively (in Example 1, the magnesium source was turned on 0.2h after the growth was started);

After testing, it is found that the four groups of samples are all Ga ₂ O ₃ films with good quality, and the light absorption cut-off edge is around 250 nm. Except for a small amount of magnesium element detected in the EDS data of samples 2-4, no magnesium element is detected in other samples. .

After the four groups of samples were prepared into UV detectors, except for sample 2-1, which had no significant effect on the response time of the device, the response time of the other samples was significantly shortened.

Example 3

In order to verify the influence of the opening time of the magnesium source in each cycle on the performance of the film, other conditions were the same as those in Example 1 except that the opening time of the magnesium source was changed. The turn-on times of the magnesium sources of the samples numbered 3-1, 3-2, 3-3, and 3-4 were: turn on 10s; turn on 60s; turn on 120s; turn on 180s. The turn-off time of each cycle of the four groups of samples is 120s, and the number of cycles is 20 times (in Example 1, the magnesium source was turned on for 30s, turned off for 120s, and repeated 20 times).

After testing, it is found that the four groups of samples are all Ga ₂ O ₃ films with good quality, and the light absorption cut-off edge is around 250nm. Except for a small amount of magnesium element detected in the EDS data of samples 3-4, no magnesium element is detected in other samples. .

After the four groups of samples were prepared into UV detectors, except for sample 3-1, which had no obvious effect on the response time of the device, the response time of the other samples was significantly shortened.

The descriptions of the above embodiments are only used to help understand the method and the core idea of the present invention. It should be pointed out that for those skilled in the art, without departing from the principle of the present invention, several improvements and modifications can also be made to the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

The above description of the disclosed embodiments enables any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims (10)

1. Ga₂O₃The preparation method of the film comprises the following steps:

taking an organic gallium compound as a gallium source, taking high-purity oxygen as an oxygen source, depositing on the surface of a substrate by a metal organic chemical vapor deposition method, and cooling to obtain Ga₂O₃A film;

in Ga₂O₃Intermittently replenishing organomagnesium compound during film growth, the time for replenishing organomagnesium compound starting with Ga₂O₃Ending in Ga 0.1-6 h after the film starts to grow₂O₃0.1-6 h before the growth of the film is stopped;

the specific mode of intermittently supplementing the organomagnesium compound is to turn on the organomagnesium compound for 10s to 600s, turn off the organomagnesium compound for 10s to 600s, and repeat the steps for 1 to 1000 times.

2. The preparation method according to claim 1, wherein the organogallium compound uses high-purity nitrogen as a carrier gas, and the flow rate of the carrier gas is 10 to 40 sccm; the flow rate of the high-purity oxygen is 100-400 sccm; the organic magnesium compound takes high-purity nitrogen as a carrier, and the flow rate of the carrier is 1-20 sccm.

3. The method according to claim 1 or 2, wherein the organo-gallium compound is selected from one or two of trimethyl gallium and triethyl gallium, and the organo-magnesium compound is selected from one or two of dimocene magnesium and dimethyl dimocene magnesium.

4. The preparation method according to claim 1 or 2, wherein the deposition temperature is 400-1100 ℃, the deposition time is 1-6 h, and the vacuum degree of the deposition is 5 × 10²～1×10⁴Pa。

5. A method of manufacturing as claimed in claim 1 or 2, wherein the substrate is selected from a sapphire substrate, magnesium oxide or magnesium aluminate.

6. The method according to claim 1 or 2, wherein the temperature reduction rate is 0.2-0.8 ℃/s.

7. The process according to claim 1 or 2, wherein the time for supplementing the organomagnesium compound is started with Ga₂O₃Ending in Ga 0.3-0.7 h after the film starts to grow₂O₃0.3 to 0.7 hour before the growth of the film is stopped.

8. The method according to claim 1 or 2, wherein the step of intermittently replenishing the organomagnesium compound is performed by opening the organomagnesium compound for 30s to 160s, closing the organomagnesium compound for 30s to 160s, and repeating the step for 10 to 100 times.

9. Ga produced by the production method according to any one of claims 1 to 8₂O₃Film, characterized in that Ga₂O₃The film is doped with trace magnesium.

10. Ga according to claim 9₂O₃A film characterized in that the magnesium content is undetectable on the EDS test.

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