CN103866379A - Method of preparing GaP film material - Google Patents

Abstract

The invention provides a method of preparing a GaP film material. The method comprises the following steps: by taking Ga2O3 and P2O5 as starting materials, mixing the Ga2O3 and P2O5 at an equal molar ratio, sealing in a vacuum ampoule, reacting under a condition of 500 DEG C-600 DEG C to generate GaPO4; breaking the ampoule, by taking hydrogen gas, hydrogen gas-argon gas mixture, active carbon, hydrocarbon, and the like as a reducing extraction agent, adopting a self-established high-temperature in-situ solid-phase extraction reaction gas-phase deposition method, under an condition with lower vacuum degree, successfully preparing the GaP film material which is controllable in thickness, grey-black, higher in degree of crystallinity, higher in purity and single in phase on different substrates such as Si, Ge, stainless steel, conductive glass and conductive ceramic. According to the method disclosed by the invention, the used materials are simple, cheap and easy to obtain, are solid or non-toxic gases which are pollution-free on environment, free of security threat on operating staff; and moreover, preparation equipment is simple, preparation period is short, adaptation on substrate material is strong, preparation cost is lower, and larger-scale preparation of GaP film material can be realized.

Description

A kind of method for preparing GaP thin film material

technical field

The invention belongs to the field of preparation of thin film materials, and in particular relates to a method for preparing GaP thin film materials.

Background technique

GaP is a synthetic III-V compound semiconductor material, and high-purity GaP is an orange-red transparent crystal. The melting point of gallium phosphide (GaP) single crystal material is 1467°C, the crystal of gallium phosphide (GaP) is a zinc blende structure, the lattice constant is 0.5447±0.006nm, and its chemical bond is mainly a mixture of covalent bonds Bond, its ionic bond composition is about 20%, and the band gap (Eg) width is 2.26eV at 300K, which is a direct transition semiconductor. Gallium phosphide (GaP) is the same as other large band gap III-V compound semiconductors. It can make the Fermi level close to the middle of the band gap by introducing a deep center. For example, doping impurity elements such as chromium, iron, and oxygen can become a semi-insulating material. . Gallium phosphide (GaP) is divided into single crystal material and epitaxial material. Industrially produced substrate single crystals are all N-type semiconductors doped with sulfur and silicon impurities.

GaP single crystal was prepared by liquid phase method at normal pressure in the early stage, and then prepared by liquid-covered Czochralski method. The gallium phosphide (GaP) single crystals produced in the modern semiconductor industry are all synthesized in high-pressure synthesis furnaces by directional solidification technology, and after appropriate treatment, they are loaded into high-pressure single crystal furnaces for single crystal pulling. Gallium phosphide epitaxial materials are produced on gallium phosphide single crystal substrates by liquid phase epitaxy or gas phase epitaxy plus diffusion growth. It is mostly used in the manufacture of light-emitting diodes (LEDs). Liquid phase epitaxy materials can produce red light, yellow-green light, and pure green light-emitting diodes, and gas-phase epitaxy plus diffusion growth materials can produce yellow light, yellow-green light light-emitting diodes.

In addition to the above-mentioned traditional methods, the usual preparation methods of III-V compound semiconductor GaP thin film materials mainly use expensive and harsh physical methods or complex and expensive MOCVD methods. The traditional method uses high-purity metallic Ga and high-purity non-metallic P to react to obtain GaP, and its chemical reaction formula is as shown in formula (1); physical methods include plasma sputtering, molecular beam epitaxy (MBE), electron beam evaporation, and pulsed laser deposition. (PLD), magnetron sputtering (MSD), etc. In the MOCVD method, GaP is prepared by reacting liquid trimethylgallium, an expensive metal-organic compound of gallium, and a highly toxic compound of phosphorus (such as gaseous phosphine PH ₃ ). The chemical reaction formula is as formula (2). These preparation methods all require extremely high equipment, and the equipment is expensive and the process is complicated.

The present inventor disclosed a method for preparing a GaP thin film material in the invention patent with the publication number CN103173715A and the publication date of 2013.06.26. The preparation method uses the vertical gradient condensation thin film deposition device disclosed by the inventor in the invention patent with the publication number of CN102517562A, using Ga ₂ O ₃ , P ₂ O ₅ and reducing extraction agent as raw materials, and reacts and deposits GaP thin film. Chemical reactions such as reaction formula (3), (4). The preparation method adopts simple equipment, uses simple raw materials, and is cheap and easy to obtain; however, the preparation process needs to be improved, and the purity and crystallinity of the prepared GaP thin film material need to be further improved.

Ga+P→GaP→GaP/subst _rate (1)

Ga(CH ₃ ) ₃ +PH ₃ →GaP+3CH ₄ ↑ (2)

Ga ₂ O ₃ +P ₂ O ₅ +8H ₂ →2GaP+8H ₂ O (3)

Ga ₂ O ₃ +P ₂ O ₅ +8C→2GaP+8CO (4)

Contents of the invention

The purpose of the present invention is to provide a method for preparing GaP thin film material, further optimize the preparation process of GaP thin film material, and improve the purity and crystallinity of GaP thin film material.

The technical scheme of the present invention is: a kind of method for preparing GaP thin film material, it is characterized in that, comprises the following steps:

Step 1. Mix Ga ₂ O ₃ and P ₂ O ₅ at a molar ratio of Ga:P=1:1, grind them evenly, add anhydrous ethanol with a mass of 50% to 100% of the solid raw material, grind them evenly, and dry them with Press it into a sheet under a pressure of 10-15MPa, then seal it in a vacuum ampoule, place the ampoule in the corundum crucible of the reactor, heat it to 500°C-600°C in a tubular electric furnace, and keep the temperature constant for 2-4 hours , naturally cooled to GaPO ₄ ;

Step 2. Break the vacuum quartz ampoule, place GaPO ₄ in the reaction area of the thin film deposition device, place the substrate in the deposition area of the thin film deposition device, use high-purity nitrogen to evacuate and replace the oxygen concentration to the ppm level, and then use Ar +H ₂ mixed gas is evacuated for 1-2 times, then evacuated to 7-13Pa, the temperature rise rate is controlled at 5-10°C/min, the reaction zone is heated to 1200°C-1250°C, and the deposition area is heated to 600°C ℃～800℃, pass hydrogen gas as a reducing extraction agent, keep the temperature for 3～4h, keep the vacuum degree ≥-0.08Mpa; then cool down to room temperature naturally, fill high-purity Ar+H ₂ mixed gas to normal pressure, the substrate The GaP thin film material is deposited on the surface.

Preferably, the thickness of the sheet is 1-10 mm. The volume of H ₂ in the Ar and H ₂ mixed gas accounts for 10%-30% of the total volume of the mixed gas.

Preferably, the reducing extraction agent in step 2 can also use hydrogen-argon mixed gas, activated carbon (C) or hydrocarbons. Further, when activated carbon is used as the reduction extraction agent, solid activated carbon should be placed in the reaction zone of the thin film deposition device.

Principle of the present invention and chemical reaction are as reaction formula (5), (6):

Ga ₂ O ₃ +P ₂ O ₅ →2GaPO ₄ (5)

2GaPO ₄ +8H ₂ →2GaP+8H ₂ O↑ (6)

The invention provides a method for preparing a GaP thin film material, using Ga ₂ O ₃ and P ₂ O ₅ as starting materials, mixing Ga ₂ O ₃ and P ₂ O ₅ in an equimolar ratio, sealing them in a vacuum ampoule, React at 500℃～600℃ to generate GaPO ₄ ; then break the ampoule, use hydrogen, hydrogen-argon mixed gas, activated carbon and hydrocarbons as reducing and extracting agents, and use self-created high-temperature in-situ solid phase High-temperature in-situ solid-state extract-like vapor deposition method, in a vertical gradient condensation thin film deposition device, under low vacuum conditions, on Si, Ge, stainless steel, conductive glass, conductive GaP film materials with controllable thickness, gray black, high crystallinity and high purity single phase have been successfully prepared on different substrates (substrates) such as ceramics. The raw materials used in the invention are simple, cheap and easy to obtain, all of which are solid or non-toxic gas, have no pollution to the environment, and have no safety threat to operators; the preparation equipment is simple, the preparation cycle is short, and the substrate (substrate) material is adaptable Strong, low preparation cost, and large-scale GaP thin film material preparation can be realized.

The GaP thin film material prepared by the invention has higher purity and better crystallinity; a sealing system is adopted in the preparation process to avoid losses caused by sublimation of raw materials, and GaPO ₄ can be generated according to the stoichiometric ratio; the process is highly controllable; and the preparation temperature is lower , save energy consumption.

Description of drawings

FIG. 1 is the XRD diffraction spectrum of GaPO ₄ obtained from the reaction in Step 1 of Example 1.

FIG. 2 is an XRD diffraction spectrum of the GaP thin film material prepared in Example 1.

Fig. 3 is the XRD diffraction spectrum of GaPO ₄ obtained from the reaction in Step 1 of Example 2.

FIG. 4 is the XRD diffraction spectrum of the GaP thin film material prepared in Example 2.

FIG. 5 is an XRD diffraction spectrum of the GaP thin film material prepared in Example 3.

Detailed ways

The present invention will be further described below in conjunction with specific embodiments and accompanying drawings.

Example 1

The method for preparing GaP thin film material, comprises the following steps:

Step 1. Accurately weigh Ga ₂ O ₃ and P ₂ O ₅ with an electronic balance of 1/10,000, mix them according to the ratio of molar ratio Ga/P=1.0/1.0 and grind them evenly. Water and ethanol, after careful grinding again, dry to remove the solvent, press it into a disc or square with a thickness of 3mm with a pressure of 12MPa, then seal it in a vacuum ampoule, and place the ampoule in the corundum crucible of the reactor , heated to 500°C in a tube electric furnace, kept at a constant temperature for 2 hours, and obtained GaPO ₄ solid material after natural cooling (its XRD diffraction pattern is shown in Figure 1);

Step 2. Break the ampoule, place GaPO ₄ in the reaction area of the vertical gradient condensation thin film deposition device, place the substrate in the designated position in the deposition area of the thin film deposition device, and replace it with high-purity nitrogen to oxygen concentration of ppm level. Then use Ar+H ₂ mixed gas (containing H ₂ volume percentage of 10% to 30%) to vacuumize and replace twice, then vacuumize to about 1mmHg, control the heating rate to 5°C/min, and heat the reaction zone to 1250 ℃, the deposition area was heated to 800 °C; when the temperature in the reaction area reached the predetermined temperature, the substrate rotation device was turned on, and the rotation speed was set at 5 rpm; hydrogen gas was introduced as a reducing and extracting agent, and the temperature was kept constant for 4 hours, during which the vacuum degree was kept constant. Less than -0.08Mpa; finally cool down to room temperature naturally, fill high-purity Ar+H ₂ mixed gas to normal pressure, open the tail gas valve, then open the deposition device, take out the deposition substrate, and obtain an orange-red GaP/substrate thin film.

The prepared GaP thin film material was detected and analyzed by Rigaku D/max XRD, and its XRD diffraction pattern is shown in Figure 2. The analysis shows that the GaP thin film material is a single phase of pure phase GaP with high crystallinity and high purity. The film measured by the step thickness gauge is equivalent to the calculated value, the error is small, and the thickness is about 2-20 μm.

Example 2

The method for preparing GaP thin film material, comprises the following steps:

Step 1. Accurately weigh Ga ₂ O ₃ and P ₂ O ₅ with an electronic balance of 1/10,000, mix them according to the ratio of molar ratio Ga/P=1.0/1.0 and grind them evenly. Water ethanol, after careful grinding again, dry to remove the solvent, press it into a disc or square sheet with a thickness of 3mm with a pressure of 12MPa, then seal it in a vacuum ampoule and place it in a quartz boat reactor. Heated to 500°C in a tubular electric furnace, kept at a constant temperature for 2 hours, and cooled naturally to room temperature to obtain a GaPO ₄ solid material (its XRD diffraction pattern is shown in Figure 3);

Step 2. Then break the ampoule, place GaPO ₄ in the reaction area of the vertical gradient condensation thin film deposition device, place the substrate in the designated position in the deposition area of the thin film deposition device, and replace it with high-purity nitrogen to an oxygen concentration of ppm level, and then use Ar+H ₂ mixed gas (containing H ₂ volume percentage of 10% to 30%) to vacuumize and replace twice, and then vacuumize to about 1mmHg; control the temperature rise rate to 10°C/min, and heat up the reaction zone When the reaction zone reaches 1250°C, the deposition zone is heated to 800°C; when the temperature of the reaction zone and the deposition zone reaches the predetermined temperature, the substrate rotation device is turned on at a speed of 5 rpm; hydrogen gas is introduced as a reducing extraction agent, and the temperature is kept constant for 4 hours. Keep the vacuum degree not less than -0.08Mpa; finally cool down to room temperature naturally, fill high-purity Ar+H ₂ mixed gas to normal pressure, open the tail gas valve, then open the deposition device, take out the deposition substrate, and obtain orange-red GaP /substrate membrane.

The prepared GaP thin film material was detected and analyzed by Rigaku D/max XRD, and its XRD diffraction spectrum is shown in Figure 4. The analysis shows that the GaP thin film material is a single phase of pure phase GaP with high crystallinity and high purity. The film measured by the step thickness gauge is equivalent to the calculated value, the error is small, and the thickness is about 2-20 μm. The film measured by the step thickness gauge is equivalent to the calculated value, the error is small, and the thickness is about 2-20 μm.

Example 3

The method for preparing GaP thin film material, comprises the following steps:

Step 1. Accurately weigh Ga ₂ O ₃ , P ₂ O ₅ , and activated carbon C with an electronic analytical balance of 1/10,000, mix and grind evenly according to the molar ratio Ga/P/C=1.0/1.0/8.0, add and solid 50% to 100% equivalent absolute ethanol as raw material, after careful grinding and uniformity, press it into a disc or square sheet with a thickness of 3mm with a pressure of 12MPa;

Step 2. Then place the sheet in the reaction zone of the vertical gradient condensation film deposition device; use high-purity nitrogen to evacuate and replace the oxygen concentration to the ppm level, and then use Ar+H ₂ mixed gas (containing H ₂ volume percentage of 10 % to 30%) vacuum replacement 1 to 2 times, the substrate required for deposition is placed in the designated position in the deposition device after treatment; then the vacuum is pumped to about 1mmHg, the temperature rise rate is controlled to 10°C/min, and the reaction zone is heated up to 1250°C, the deposition area was heated to 800°C; the temperature was kept constant for 4 hours, and the vacuum degree was kept at not less than -0.08Mpa; finally, the temperature was naturally cooled to room temperature, and the exhaust gas valve was opened after filling high-purity Ar+H ₂ mixed gas to normal pressure. Take out the deposition substrate from the reactor, and then reduce and purify it for 4 hours under the atmosphere of flowing pure hydrogen or high-purity Ar+H ₂ mixed gas to obtain the GaP/substrate thin film.

The prepared GaP thin film material was detected and analyzed by Rigaku D/max XRD, and its XRD diffraction pattern is shown in Figure 5. The analysis shows that the GaP thin film material is a single phase of pure phase GaP with high crystallinity and high purity. The film measured by the step thickness gauge is equivalent to the calculated value, the error is small, and the thickness is about 2-20 μm.

Claims (4)

1. A method for preparing GaP thin film material, is characterized in that, comprises the following steps: Step 1. Mix Ga ₂ O ₃ and P ₂ O ₅ at a molar ratio of Ga:P=1:1, grind them evenly, add anhydrous ethanol with a mass of 50% to 100% of the solid raw material, grind them evenly, and dry them with Press it into a sheet under a pressure of 10-15MPa, then seal it in a vacuum ampoule, place the ampoule in the corundum crucible of the reactor, heat it to 500°C-600°C in a tubular electric furnace, and keep the temperature constant for 2-4 hours , naturally cooled to GaPO ₄ ; Step 2. Break the vacuum quartz ampoule, place GaPO ₄ in the reaction area of the thin film deposition device, place the substrate in the deposition area of the thin film deposition device, use high-purity nitrogen to evacuate and replace the oxygen concentration to the ppm level, and then use Ar +H ₂ mixed gas is evacuated for 1-2 times, then evacuated to 7-13Pa, the temperature rise rate is controlled at 5-10°C/min, the reaction zone is heated to 1200°C-1250°C, and the deposition area is heated to 600°C ℃～800℃, pass hydrogen gas as a reducing extraction agent, keep the temperature for 3～4h, keep the vacuum degree ≥-0.08Mpa; then cool down to room temperature naturally, fill high-purity Ar+H ₂ mixed gas to normal pressure, the substrate The GaP thin film material is deposited on the surface. 2. A kind of method for preparing GaP thin film material according to claim 1, is characterized in that, the reducing extraction agent described in step 2 adopts hydrogen, hydrogen-argon mixed gas, gac or hydrocarbon. 3. A method for preparing a GaP thin film material according to claim 1, wherein the thickness of the sheet is 1-10 mm. 4. A method for preparing a GaP thin film material according to claim 1, wherein the volume of _H in the Ar and _H mixed gas accounts for 10% to 30% of the total volume of the mixed gas.

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