TW477823B - Method and application for preparing ZnSe thin films by ion-assisted cw CO2 laser deposition - Google Patents

Abstract

Zincselenide (ZnSe) films were grown on quartz glass and GaAs (100) substrates by continuous wave CO2 laser with ion beam assisted deposition. The ZnSe films are applied for (1) multilayer anti-reflection coatings (2) blue light emitting devices. There are some advantages for this technique over the ion-beam coating, MBE, MOCVD and PLD methods for fabricating layered semiconductors: (1) it is cheaper and safer than ion-beam coating, MBE and others. (2) To heat the target locally by using laser that could reduce contaminations and heat radiation. (3) To avoid the splash of PLD.

Description

477823

Λ Edge ^ Ming stupid (1 pain --------: I

… I '7 ^ —industry L-Jiy —. Field The present invention uses a continuous carbon dioxide laser and ion assisted system, the bond growth of the zinc film on the quartz glass and gallium halide substrate, ^, stop learning multilayer film And anti-reflective coating, and blue light emitting elements. & Background, A layer of zinc selenide thin film was plated on the substrate to manufacture a coating and blue light-emitting 7G parts. Organic metal vapor deposition (MOCVD) and molecular beam epitaxy can be applied. Among them, organometallic vapor deposition has been applied to arsenide substrates. The sub-beam epitaxy method can also grow gallium nitride epitaxes on gallium arsenide substrates and sapphire substrates. ^ The current epitaxial method is dominated by the seeded beam stupid method; organic metals and organic metals are used as raw materials, so they are more expensive and difficult to mass produce. Organic metal chemical vapor deposition and chemical vapor deposition are dangerous due to their use; molecular beam epitaxy is more expensive

Organometallic molecules are deposited into the reaction chamber and deposited on the substrate surface. The conventional technique of organometallic vapor deposition (MOCVD) is a precursor, which is transmitted through an appropriate gas pipeline, and the reactant is exposed to high temperature on the substrate. Thermal decomposition

Page 6 5. Description of the invention (2) Form a thin film. There is something emerging from the growth of the Shixi chemical word film, ^

Stutius # A ^ 1 978 ^ Appl. Phys. Published this technique to grow a selenide film on a gallium arsenide substrate. The formula is a dimethyl zinc and selenium hydride button A ^ Danfeng Changwanson Α ^ knife and J is the precursor of zinc and selenium, at 300-350 C substrate > dish, the growth rate is about 2 Dragon / hr, for. .15 In the condition of Tori, the ratio of smashing to zinc in a gaseous state is 5: wide, and high-quality smashing crystals can be grown. [射 = 石 西化 词 U0G) The material has the narrowest FWHM, showing the best quality of thin media ^ at room temperature. After analysis by light excitation spectrum, the results also show the tuned-band-gap spectral line at 447⑽, And there is no obvious defect, it is a high-quality photoepitaxial layer. In addition, Simpson & Williams published Surface Science Science, Issue 46, Page 27 in 1990, using organic metal vapor deposition technology to grow zinc selenide on a gallium arsenide (100) substrate. It is a precursor of selenium using difluorinated zinc and diethylselenium. Within the temperature range of 275-350 °, a high crystallinity zinc selenide single crystal can be grown. In addition to the use of organometallic vapor deposition methods, in addition to growing high-quality selenide films, in recent years, it has also extended its tentacles to gallium nitride epitaxy, which is also a blue light-emitting element. 1 ((^ & 73311 丨 et al., Published in 1979)] 1) 11 j Appl. Phys 36th p. 2592 reported that DMHy and trifluorenylgallium were the precursors of nitrogen and gallium, respectively. It can improve the disadvantages of the traditional growth of gallium nitride at temperature (> 1000 ° C). It adopts two growth methods. The first growth method is to grow the low temperature gallium nitride buffer layer at 530 ° C, and then The gallium nitride epitaxial layer is grown at a high temperature of 77 ° C. The second growth method is 477823. V. Description of the invention (3) After the aluminum nitride buffer layer is grown at 70 ° C, the temperature is 85.0 ° C. The second analysis of the growth of the epitaxial layer of gallium nitride shows that in the second growth mode at 85 ° C, the proportion of the 'five-two family' is about 60 times, and the total system pressure is about 3,000 Torr. Another thin-film epitaxial technique commonly used to grow high-quality epitaxy is the molecular beam epitaxy, which uses the atomic state to be heated in an ultra-high vacuum environment to make it thermally tampered with and then fires on the substrate surface to generate a reaction. An epitaxial layer is formed. ReichOw et al. Used this technique to deposit zinc selenide epitaxy on a gallium arsenide substrate in 1983, Zinc is passed through the zinc atom gas flow before the reaction to block the formation of digallium triselenide. At 330 350 C / JEL, i_2 # m thin zinc film is grown. When measured by X-ray diffractometer, Zinc (400) peak half-height width can be as narrow as 2000arCSeC • represents excellent film crystalline quality. Sou et al. 1 '995 j'rowth ^ 147 # ^ 391 ^^^^^^^ .¾ ^ # Day 1-ray diffraction analysis. The growth method is to preheat the impure impurities, pass 1 ☆ clock zinc atomic gas flow 5 (ΤΓ Λ flow, keep the ratio of pressure to selenium 1: 3.3, so for 27, the growth rate is about 0.18-0.36 heart / h, and the thickness can be grown i 4; this is the zinc. After high-resolution [ray diffraction analysis, it can be said: can 2 ί 'can also reach 200 arcsec • full It appears that the molecular beam is used to grow a zinc selenide film with very good crystallinity. Gallium 3 looks like a long one: the same way 1 can grow a high-quality nitrogen film. Kuromoto et al. 1998 Posted in Appl. Phys.

Page 8 477823 V. Description of the invention (4)

Lett., No. 73, p. 2305 reports that high-quality gallium nitride epitaxy is grown on sapphire substrate f at 800 ° C. It uses triethylgallium and radio frequency nitrogen electrodeposition source as the source of gallium and nitrogen. At a growth rate of about 0.35 # m / h, X-ray and photoexcitation spectroscopy are used to determine that this method can grow. High-quality GaN epitaxy. U.S. Patent No. 4 8 6 0 0 7 is a method for manufacturing crystal ZnSe, the steps are as follows: (ι) polycrystalline znse

Formed into a stick-shaped starting material and placed in a reaction tank; (2) filled with a mixture of inert gas, nitrogen, and H] Se between 0.1 and 100 Torr; (3) passed the high temperature zone at a movement rate of 5mm / day, The ZnSe polycrystalline material is transformed into a ZnSe single crystal material. U.S. Patent No. 4584053 is a method for preparing a large area single crystal (ZnSe single crystal), which has high quality and low impurities and can be used as a substrate material for epitaxial growth. The main methods include firstly ore-smelting polycrystalline ZnSe by CVD method, sealing in a capsule, forming a single crystal material through high temperature and high pressure, and being an epitaxial substrate material. U.S. Patent No. 51 74854 is a method for making ZnSe crystals (Crystal growth of group II-Vi compound Semiconductor). The steps are as follows: in a high temperature state, about 6-9 atm of Se is dissolved in the Zn solvent to saturation. State; placing the substrate in a low temperature environment can grow a Z n S e single crystal. US Patent No. 56 1 6 1 78 is a method for preparing type ZnSe by using organometallic chemical vapor deposition. This method uses a p-type doped organic substance as the starting material. This substance must include at least one nitrogen atom and two atomic groups with a molecular weight greater than 12. One of them is di-isopropylamine. nice

477823 V. Description of the invention (5) National Patent No. 5 1 9241 9 is a method for growing a high-quality P-type ZnSe by electrochemical deposition method (Method for producing a zinc selenide blue 1 i gh t em i 11 i ng device ), The method involves immersing an anode containing zinc and a ZnSe single crystal substrate in a solution containing ion and ion. The current is conducted from the zinc anode to the n-type ZnSe substrate cathode. Finally, P-type ZnSe is deposited on the n-type ZnSe cathode to form a pn_junctiON ZnSe semiconductor. U.S. Patent No. 55542 119 is a method for growing single crystal blocks by using a high-pressure melting method, such as a vertical Bujimanan furnace. In this method, polycrystalline ZnSe is used as a seed, and after melting at high temperature, a ZnSe single crystal material of South quality can be grown through an appropriate procedure. US Patent No. 5015327 is a method for growing a ZnSe film on a ZnSe substrate, including the following steps: (1) heating the znSe substrate from 25 0 ° C to 450 ° C under a pressure of 0.1-10 Torr hydrogen; (2) Pass in Zn (CH3) 2 * Zn (C2H5) 2 and ISe gas, so that the molar ratio of Se to Zn is between about 10 and 100. Under this condition, a ZnSe film can be grown on a ZnSe single crystal substrate. . OBJECTS OF THE INVENTION The main purpose of the present invention is to disclose a continuous carbon dioxide laser and ion assisted system 'method for depositing a zinc selenide film on a substrate to produce an optical multilayer film and an anti-reflection coating film, which can generate a blue light emitting element. Graphic description:

Page 10 477823 V. Description of the invention (6) Figure 1: Schematic diagram of evaporation equipment: Sub-source A: Continuous CO2 laser B: Mirror C: Focusing lens D: Vacuum cavity E: Substrate support frame and heater F : Quartz oscillating film thickness monitor G: Shroud Η ·· Zinc selenide target I: 3 cm Grafman type (Kaufman-Type) Grape J: Heat-resistant boron nitride K: Mechanical pump L: Diffusion pump M: Condensation block N: Gate valve Figure 2. X-ray diffraction pattern of Shixi Zn film, using zinc selenide / quartz auxiliary device at a wavelength of 700 (Α) Shixi chemical powder (B) room temperature · (C) 150 ° Selenide at C / Quartz (D) Zinc Selenide / Quartz + Ion Beam at 150 ° C Figure 3. Variation of refractive index n and extinction nm at different evaporation rates, ^ 823823 V. Description of the invention ( 7) Film thickness 5 5 0 nm

Substrate temperature: 15 0 ° C Figure 4. Changes in nm at different substrate temperatures, evaporation rate: 6.4 Refractive index n and extinction coefficient k at a wavelength of 700 Angstroms / second, film thickness: 550 nm Figure 5 = Ion Beam-assisted mineralization conditions, the distribution of n when the ion beam current is changed, f plating rate: 9 · 0 angstroms / second, film thickness: 550 nm, substrate temperature: 150 ° C

(A) 20 mA (B) 10 mA

(C) 15 mA

Fig. 6 k-distribution of j-beam assisted evaporation conditions when ion beam current is changed

, Plating rate. 9.0 Angstroms / second, film thickness · 55 ° nm, substrate temperature: 150 ° C

, Α) 2〇ΠΐΑ r D Λ 1 r A

W 15 mA (C) 10 mA

Different Ion Beam Current Pulldown (A) Without Ion Beam Assistance

(C) 15 mA Figure 8 shows the change of the Mann spectrum of the eight-stone siliconized zinc film in different stones.

(B) 10 mA

(D) X-ray diffraction at 20 mA gallium substrate temperature

(A) 100 ° c (D) 300 ° c (B) 150 t

(E) 350 ° C (C) 200 t:

(F) 400 ° C

477823 V. Description of Invention (8)

Figure 9 Changes in Raman spectrum at different substrate temperatures (A) 1 0 0 ° C (B) 1 5 0 ° C

(C) 200 ° C (D) 30 0 ° C

(E) 350 ° C (F) 40 0 ° C Figure 10. Low temperature photoexcitation spectrum of 2 0 K of zinc selenide film at 400 ° C

Figure XI Excitation spectrum of Shixihua Ci film at 400 ° C (A) 300K (B) 250K

(C) 200K (D) 150K

(E) 100K (F) 50K

(G) 20 K, detailed description of the invention

The invention mainly discloses a continuous carbon dioxide laser and ion-assisted method for electroplating a grown selenide film on a substrate to manufacture light and anti-reflection coatings. The manufacturing method is suitable for quartz glass and arsenic ί ::: zinc substrate (ZnSe) or sapphire substrate, and a selenide film and a gallium nitride film are grown on the # substrate.

477823 V. Description of the invention (9) and anti-reflection coating, can be used as blue light emitting element. The present invention uses continuous carbon dioxide laser irradiation to irradiate a target made of polycrystalline granular petrochemical zinc (99. 9%), and then vaporizes the target on gallium arsenide (and quartz glass substrate) after heating. Assisted growth with argon ion beam. The process parameters of the continuous carbon dioxide laser vapor-deposited zinc film vary with different substrates; the process pressure of the quartz substrate is 1 X γ 0.3-1 X 10, torr , The process temperature is 25 ~ 400t, the growth rate is 3.6 ~ 20.2 A / sec, the carbon dioxide laser power is 6-70 watts, the ion beam current of auxiliary plating is 10 ~ 20 mA, and the auxiliary evaporation The ion beam is 100 ~ 350 V. The process pressure on the gallium arsenide (100) substrate is} chuan · 3 (~ 1 X ίο · 6 t〇rr, the process temperature is 25 ~ 40 (rc, the growth rate is 2 8 ~ 20 A / sec. The method of removing the oxide layer on the surface of the substrate is to bombard with a chemical solution of ammonia: hydrogen peroxide: water = 3: 1: 15 and argon ion beam (100 ~ 35〇ν, 10 ~ 25 mA). ~ 20 minutes. Figure 1 is a schematic diagram of the evaporation equipment, including vacuum pumps for machine pumps and diffusion pumps, which can be pumped up to 5X 10-6: t〇rr, the cavity has a built-in First, the beam generator is used to assist the growth of the film and clean the substrate. The steps are to charge the gas into the Discharge Chamber and Plasma bridge neutralizer, dissociate into argon ions, and accelerate the emission at two f. A plasma neutralizer is used to generate an electron cloud to form a neutral plasma. By controlling the flow of argon gas, and the ion beam voltage (100-350V), the electricity is explained on page 14 (5). 25mA), you two people X always use feedback laser power; ^ f # device to detect film thickness' A / s). (2.79 ^ 20.2 between room temperature to 400 ℃, can To get the sunset, change the control gate J ^ to the poly and single crystal structure. With the X-ray diffractometer, pull @ 吾 ,, mesh, 丨 μ μ ^ ^ ^ $ 11 ^ ^ ^ ^ The measurement system and the optical laser spectrum are described in two parts: 刀, 刀 为 石 * 破 璃 and 化 GaN 镓 (001) Substrate 1 · Applied to a quartz substrate ·· = Second is the χ # line diffraction of the zinc selenide film Figure, 0 10Q torr, process temperature is 25 ~ 400 t, growth J rate is 3.6 ~ 20.2 A / sec, carbon dioxide laser power is 6-7 watts The ion beam current is 10 ～ 20mA, and the ionic electricity waste for auxiliary vaporization is 1 field 00 ～ 35 ". The medium grows at 150 °, has ion beam assist shape, and has the best film quality. Figure The third is the change of ^ η and extinction coefficient k at a wavelength of 700 nm at different evaporation rates. Figure 4 changes the temperature of η and k at 700 nm for different substrate temperatures. It is shown at /: Good optical quality. Figures 5 and 6 show the distribution of n with ion beam assisted and = plating conditions when the ion beam current is changed. It is shown under the current and voltage process conditions of 20 0V. Single crystal bulk material at 700 ⑽ !! The value is 2.54〇, which is very close to the value of 477823. V. Description of the invention (11) / In addition, it is shown that the addition of ion beam assist has indeed reduced the effect of selenization. Figure 7 shows the Raman spectra of different ion beam currents. The film crystallinity is lower than that of ion-assisted ion beams. The above measurement results can be used to establish high levels. Growth conditions of the selenide film of the mouth. 2. Use on a gallium arsenide (GaAs, 100) substrate, process pressure ° ~ 1 X 10 = torr, and process temperature 25 ~ 400. (: Cheng H production is 2 · 8 ~ 20 A / sec, the method of removing the oxide layer on the surface of the substrate is dagger: water = 3: 1: 15 chemical solution and argon ions; t50v, 10 ~ 25 mA) bombardment minute. Fig. 8 is an X-ray diffraction pattern of a selenide film at a substrate temperature (from 100 to 4000c), showing peak changes such as "'200" and (400) planes, respectively. Under the low temperature growth (less than 20%), the presence of the dizinc (111) plane 'represents that the thin film grown at this time still belongs to the structure of Xiyue. At any time, the substrate temperature rises, and when it is greater than 200, it appears The increase and decrease of the peaks of zinc selenide (m), (200) and (400) are centered at 400C, and the growth can be best. Figure 9 shows the change of Raman spectrum when the plate temperature is not too high. It shows that under 400 t growth conditions, there is minimal stress between the gallium selenide substrate and the gallium substrate. Figures 10 and 11 show the light laser spectrum of the 4000C petrified ^ thin film, showing excitons (excit 〇n) and the donor acceptor pair and its relationship with temperature changes. The method disclosed in the present invention uses a continuous carbon dioxide laser to grow a zinc selenide film on a gallium arsenide substrate , Using a laser beam in a vacuum environment, continuously

Page 16 477823

Compared with the organic safety, thin heating and heating is cheaper and cheaper, as well as reducing the heat, which results in the production of blue and full-color laser-reading and long-lasting products, which are major technical zinc blocks, and the growth method and safety of metal chemical gas film are relatively radiant; It can avoid photodiodes and kanbans with poor film quality, and blue-violet writing heads, so that high-quality light-emitting phase deposition method can be used. This method (with pulse-free pulse type, etc.) The current optical disc rate and industrial and molecular beam emission of the above-mentioned blue laser detectors have the advantages of localized heating and laser sputtering in equipment. The important foundation of Shixi, and its replacement A certain crystal method for improving the data for a long life is that the cost is lower than that of the target material, and the common zinc is thinner. Blue light is currently about 4 times the component of CD. The quality and phase are both economical and the above methods reduce the growth of the contaminated liquid droplets from the film. Yes, DVD, etc. So it can become the current

Claims (1)

477823 —Two H options ”1 丨 Beam-assisted continuous carbon dioxide laser vapor deposition of zinc selenide thin family on quartz glass substrate, in which continuous carbon dioxide vapor deposition of zinc selenide thin film on a quartz substrate process pressure is 10 · 3 ~ 1χ 1〇-6 ± 〇1 ^, process temperature is 25 ~ 40 ° (:, growth rate is 3.6-20.21 | / sec, carbon dioxide laser power is 70 watts, assisted evaporation of _ beam current It is 10 ~ 20mA, and the voltage of the ion beam to assist the evaporation is 100 ~ 350V 〇2. If the method of the scope of the application for the patent application item 丨, you can choose quartz glass and arsenic substrate 砸 ZnSe substrate, or sapphire substrate 3. If the method of the first item of the scope of application is applied, its application is to grow zinc selenide film and gallium nitride film on the above substrates. I. A continuous carbon dioxide laser vapor deposition selenization assisted by ion beam. Method for forming zinc thin film on quartz glass base plate to manufacture optical multilayer film and anti-reflection coating. · A method of ion beam assisted continuous carbon dioxide laser vapor deposition of zinc selenide film on gallium bell substrate, in which the continuous type Zinc Selenide Film The manufacturing process of the gallium arsenide (100) substrate is ΐχ, 'torr, the process temperature is 25 ~ 40ot, the growth rate is y / 4_sec, and the method for removing the oxide layer on the substrate surface is ammonia water, hydrogen peroxide, water = 3. : 1: 1: 5 chemical solution and argon ion beam 477823 6. Application for patent scope I (100-3 50V, 10 ~ 25mA) Bombing for 20 minutes 4 I 9a? 〇 ^ βιPage 19