TWI404129B - Method for manufacturing carbon film with semiconductor properties - Google Patents

Abstract

Disclosed is a manufacturing method for semiconductor diamond-like carbon film, in which a radio frequency magnetron sputtering method is used to fabricate boron-doped diamond-like carbon (B-DLC) film on silicon substrate, where the boron tablet is embedded in the graphite target as a composite target and the boron tablet is the doping source. After the boron-doped diamond-like carbon film is formed, the film is annealed at 500 degrees Celsius for 10 minutes, and then Hall effect and four-point probe analysis are performed to analyze its carrier density and resistance rate respectively. It is proven that the polarity of the boron-doped diamond-like carbon film is the p-type semiconductor characteristics, and the carrier density can be as high as 1.3 *10<SP>18 </SP>cm<SP>-3</SP> and the resistance rate is around 0.6 &OHgr;-cm; therefore, the boron-doped diamond-like carbon film of this invention has excellent semiconductor characteristics and high-temperature stability, and will have superior applications and developments on solar cell or electronic transmission, and electrode elements and equipments.

Description

Method for manufacturing semiconductor-like diamond-like carbon film

The invention relates to a method for manufacturing a semiconductor-like diamond-like carbon film, in particular to a semiconductor-like carbon film material, and a related design technique of the process and the raw material target; the semiconductor of the invention Drilled carbon films can be applied to electronic and optoelectronic devices and components, such as solar cells, semiconductor components, wires and electrodes of electronic components.

It can be used as a high protective material and anti-wear by using diamond film and diamond like carbon, which are mainly possessed by high visible light and infrared (IR) penetration, high mechanical strength, high electrical resistance, gas corrosion resistance or corrosive medium. Reflective coating. Due to the energy crisis, the research of thin film solar cells has attracted the attention of many experts and scholars. The diamond material has the same atomic structure as the twin crystal, and the twin crystal has unique semiconductor characteristics and can be applied to semiconductor components and solar cells. While diamond materials have the same structure as twinned materials, they are inherently insulating. Therefore, many studies hope that the doping technology will change the electrical properties of diamond materials into semiconductors or conductors, which is more conducive to diamond materials. Application and development. By doping to change the resistance value of diamond film or diamond-like carbon (DLC) film, diamond film or diamond-like carbon film can be applied to semiconductor or electrical components, and the method of reducing diamond film or diamond-like carbon resistance is mixed. Heterophosphorus or diborane, mixed to form a metal film, and nitrogen gas is infiltrated during film deposition.

At present, most of the diamond film or diamond-like carbon film for semiconductor characteristics is manufactured by chemical vapor deposition (CVD), but CVD requires expensive equipment and toxic in the process. Or flammable alkane gas to high temperature The chemical reaction generates and produces a diamond film or a diamond-like carbon film. Therefore, the semiconductor diamond-like carbon film which is desired to be developed by the present invention can be produced by a magnetron sputtering method which has no high temperature action, no chemical reaction, no flammable or toxic gas, and is likely to produce a p-type semiconductor diamond-like carbon film ( p-DLC). So far, no report has been made to make a p-type semiconductor like carbon film by RF magnetron sputtering. This study can be used as the first step in the development of semiconductor-based carbon film by boron doping in a diamond-like carbon film process. It is expected that diamond-like carbon films will have better semiconductor electrical properties than diamond films.

Boron is the most likely element to be doped into the diamond. Because the atomic radius of the boron atom is close to that of carbon, it can be substituted and incorporated into the diamond structure without a significantly distorted lattice, and can be determined as p-type doping. The semiconductor diamond (p-Diamond) can greatly improve the electrical properties of the diamond film. In this invention, an attempt is also made to dope boron-to-drilling carbon film coating by RF magnetron sputtering to adjust the area ratio of the carbon target-boron ingot as a parameter to study the electrical properties of the semiconductor relative to the doping amount. influences.

The patents of the diamond-like carbon film process and the diamond film process technology for semiconductor characteristics are as follows: 1. U.S. Patent No. 7,393,717: discloses the fabrication of a resistive region and a contact connection resistor region. Its resistance zone contains conductive diamonds. The resistive zone is a resistive layer consisting of a small portion of non-conductive diamond to the top of the substrate. The deposition of diamonds is by CVD, MWPECVD (microwave plasma), Hot Filament CVD (hot filament) or hydrogen methane plasma. The inclusions contained in the diamond make the diamond a p-type semiconductor, and the dopant contains at least one of the following components: boron, sulfur, phosphorous, diamond-like carbon (DLC). ), lithium, hydrogen, nitrogen or sp ² -bonded carbon.

2. U.S. Patent No. 7,223,442: discloses a method of preparing a diamond-like carbon nanocomposite film doped with basic elements such as carbon, germanium, metal, oxygen and hydrogen. The film preparation method is as follows: a substrate is placed in a vacuum chamber and deposited, and the substrate is biased by 0.3 to 0.5 kV; when the gas plasma is discharged, the carbon particles generate plasma energy density exceeding 5 kW-h/g-atom, and The organic compound is mixed and evaporated into the plasma; the particle beam of the dopant is guided into the plasma; the film is grown on a substrate to grow a carbon-doped conductive nanocomposite film having atomic concentrations of carbon, metal and lanthanum The proportional relationship has been confirmed first. The surface of the film is coated with a layer of ruthenium dioxide. A unidirectional current is applied to the film to cause electrothermal heating onto the film. The doped diamond-like carbon nanocomposite film has a multilayer structure to be prepared.

3. U.S. Patent No. 5,635,258: discloses a method of preparing a boron-doped diamond film using microwave plasma chemical vapor deposition (MP-CVD). The binary system reaction gas composition is C _x H _y -CO ₂ and C _x H _y O _z -CO ₂ , and the dopant is Trimethyl borate.

4. Republic of China Patent No. 594853: discloses a method for producing a diamond film using a chemical vapor phase synthetic diamond film. Forming a doped layer on the surface of the substrate of the synthetic diamond film is coated on the substrate by a solution of solid solution such as boron, boron trioxide or boron nitride; or as a target in a solid state, formed by sputtering Doped layer. The final step consists of performing a heat treatment.

5. Republic of China Patent No. 591131: A method of producing a diamond film using a gas phase reaction to produce a diamond film. A gas mixture is formed between the B(OCH ₃ ) ₃ gas and the source gas, and boron is used as a dopant source in the gas to precipitate a diamond film on the substrate by a gas phase reaction. The volume concentration of the B(OCH ₃ ) ₃ gas and the material gas is set to be 0 Vol.% or more and 8 Vol.% or less.

6. U.S. Patent No. 6,939,794: discloses a hard reticle composed of boron-doped amorphous carbon and a method of making the reticle. Amorphous carbon reticles provide improved resistance to corrosion from a variety of materials. The boron-doped amorphous carbon film is prepared by a PECVD method using a semiconductor substrate such as a semiconductor wafer as a substrate, a cavity temperature of 400 ° C to 650 ° C, introduction of propylene gas, and a gas flow rate of 300 sccm. And between 1500sccm. Diborane gas is also introduced, and the gas flow rate is between 100 sccm and 2000 sccm. While the propylene is introduced, the power range is adjusted to between 100 W and 1000 W, and the pressure is between 0.4 Torr and 0.8 Torr.

7. U.S. Patent No. 7,144,753: discloses a boron-doped nanocrystalline diamond having conductivity. Boron-doped diamonds use boron in the crystal as a charge carrier, and are particularly effective when diamond is used for the oxidation-reduction reaction of electrochemical electrodes and the elimination of aqueous solutions. In this study, it was found that the doping of boron can change the electronic insulating properties of the diamond material into the electronic properties of the conductor.

In the above patent, when a diamond material attempts to intensively incorporate a heterogeneous element to change the semiconductor properties of the diamond material, how to use the doping element to be placed in the diamond material to achieve a high carrier concentration semiconductor characteristic; multi chemical vapor synthesized diamond material, doping element for the multi-trimethyl borate (trimethyl borate) or methyl boronic ester _{B (OCH 3) 3 (Trimethylphosphite} ) gas like manner, the gas and raw material gas to dope Mixing, doping purposes are achieved by the reaction synthesis process. Synthetic diamond material or diamond-like film by chemical vapor phase, which is expensive due to chemical vapor synthesis equipment, and the reaction source is mostly in the gas phase state, so it has parameter instability and high temperature chemical reaction danger in the synthesis process, etc. factor.

It can be seen that the above-mentioned conventional and current methods are not a good design and need to be improved.

In view of the shortcomings derived from the above-mentioned conventional methods, the inventors of the present invention have improved and innovated, and after years of painstaking research, finally succeeded in research and development of the manufacturing method of the semiconductor-like diamond-like carbon film.

The object of the present invention is to provide a method for manufacturing a semiconductor-like diamond-like carbon film, which can provide a method for preparing a carbonaceous film material with semiconductor characteristics and a target material design method, and can effectively realize a carbon-coated film of semiconductor characteristics ( Diamond like Carbon) is prepared and meets the requirements of semiconductor component characteristics.

A method for manufacturing a semiconductor-like diamond-like carbon film which achieves the above object of the invention is a method for forming a composite target for sputtering using a solid-state graphite target and a boron ingot method by using a magnetron sputtering method, and embedding a boron ingot into a graphite target In the common sputtering method, a diamond-like carbon film is deposited and simultaneously doped with boron element, and the film material is doped into the diamond-like carbon film by using boron element, so the diamond-like carbon film has p Type semiconductor-like carbon film and high carrier concentration characteristics, and make the semiconductor-like carbon film is very advantageous as a material application in the semiconductor field; After the process, the semiconductor diamond-like carbon film is comparatively analyzed with boron-doped and undoped diamond-like carbon films. When the semiconductor-based carbon film is subjected to semiconducting quality measurement, the boron-containing carbon film is shown as p. Semiconductor film, and XPS analysis confirmed that the film has boron doping; the present invention can solve the bottleneck of current semiconductor materials, at the nanometer scale, semiconductor carrier concentration, carrier mobility and heat dissipation efficiency, It can be solved by semiconductor-like carbon film.

Referring to FIG. 1A and FIG. 1B, FIG. 1 is a structural diagram of a composite target of a method for manufacturing a semiconductor-like diamond-like carbon film according to the present invention. As can be seen from the figure, the main composition of the composite target 1 includes: a graphite target 11; A plurality of boron ingot sheets 12 are embedded in the graphite target 11, and the plurality of boron ingot sheets 12 have a purity of 95% or more and are a doping source, and the doping amount is a plurality of boron ingot tablets. The area ratio of 12 to the graphite target 11 is used as a modulation parameter (the filler of the boron ingot 12 accounts for 0.1% and 40% of the total target area, and the total target volume percentage is 0.1% and 60%). Between the other, the boron ingot sheet 12 may be embedded in the graphite target 11 or the carbon target in a circular, rectangular or arbitrary shape; and the doping source is in addition to boron (B), boron carbide (B ₄ C), three Other boron-containing compounds such as boron oxide (B ₂ O ₃ ) and boron nitride (BN), other boron compounds may also be used as doping elements of diamond-like carbon films; a copper plate 2 is disposed in composite Below the target 1, for supporting the composite target 1; when the composite target 1 is set, the sputtering of the semiconductor-like carbon film is started. The process is set to a sputtering power of 300 W, and argon gas is introduced as a plasma-excited gas. When a boron-containing carbon film is deposited on a high-impedance substrate (undoped germanium wafer or other substrate such as glass) After the temperature of the substrate of the carbon-impregnated film is between 250 ° C and 800 ° C, the semiconductor diamond-like carbon film is further annealed at 500 ° C, and then the semiconductor characteristics of the semiconductor-like carbon film are analyzed, and the Hall effect is used. The measurement system (HMS-3000 MANUAL Ver 3.1) measures the surface resistivity of the film and the carrier concentration and mobility, respectively; and the boron-containing semiconductor diamond-like carbon film can realize the p-type semiconductor polarity and high carrier concentration characteristics. In order to meet the requirements for the use of semiconductor components, and the area of the doped boron ingot and the thickness of the thin film deposition affect the properties of the semiconductor-like carbon film, therefore, for three different boron ingot to carbon target area ratios (0%, 6%, 12.5%), as three embodiments of the present invention; in the first embodiment of the present invention, the boron ingot to carbon target area ratio is 0%, the sputtering power is 300 W, and argon gas is introduced as Plasma-excited gas, diamond-like carbon film After accumulating on the high-impedance ruthenium substrate, the diamond-like carbon film is further annealed at 500 ° C; after semiconductor analysis and analysis (see Table 1 for analysis), the n-type boron-free diamond-like carbon film is used before annealing. After annealing at 500 °C, the n-type semiconductor film is still maintained, and its carrier concentration is slightly increased, and its carrier concentration is increased from 4.4×10 ¹⁵ cm ^-3 before annealing to 8.6×10 ¹⁶ cm ^-3 after annealing. In the second embodiment of the present invention, the area ratio of the boron ingot to the carbon target is 6%, the sputtering power is 300 W, argon gas is introduced as the gas excited by the plasma, and the diamond-like carbon film is deposited on the high impedance. After the substrate, the diamond-like carbon film is further annealed at 500 ° C; after semiconductor analysis and analysis (see Table 1 for analysis), the original n-type boron-containing carbon film is annealed after annealing at 500 ° C. The p-type semiconductor film type, and its carrier concentration is increased from 4.7 × 10 ¹⁵ cm ^-3 before annealing to 1.3 × 10 ¹⁸ cm ^-3 after annealing, and is converted into a p-type semiconductor film type after annealing because The thermal energy provided by annealing causes thermal and thermal interaction between boron and carbon atoms Diffusion, thereby forming boron-carbon bonding and p-type semiconductor characteristics; in a third embodiment of the present invention, the boron ingot to carbon target area ratio is 12.5%, the sputtering power is 300 W, and argon gas is introduced as a plasma The excited gas, the diamond-like carbon film is deposited on the high-impedance ruthenium substrate, and the diamond-like carbon film is further annealed at 500 ° C; after semiconductor analysis and analysis (see Table 1 for the analysis data), the boron-containing diamond carbon film is annealed. A p-type semiconductor diamond-like carbon film has been formed before, and after annealing at 500 °C, the p-type semiconductor film pattern is maintained, and the carrier concentration thereof is slightly increased, and the carrier concentration before annealing is 4.3×10 ¹⁵ cm ^{-3 .} And after annealing, it is raised to 2.4 × 10 ¹⁶ cm ^-3 .

Please refer to FIG. 2 , which is a C1s region analysis scan chart of a carbon-coated carbon film for XPS analysis of a method for manufacturing a semiconductor-like diamond-like carbon film according to the present invention. The coating condition of the present invention is that the ratio of boron ingot to carbon target area is 0%, respectively. 6% and 12.5%, the sputtering power is fixed at 300 W, argon gas is used as the gas excited by the plasma, the diamond-like carbon film is deposited on the high-impedance ruthenium substrate, and the diamond-like carbon film is further subjected to X-ray photoelectron spectroscopy. (XPS) analysis; it can be seen from the figure that the diamond carbon film of the original undoped boron (doping of boron ingot and carbon target area ratio is 0%), the spectral data of the C1s range of XPS is processed by Gaussian peak. The characteristics of sp ² , sp ³ and C-O bond characteristics were analyzed, and the bond energies were 284.4 eV, 285.3 eV and 287.9 Ev, respectively, and the doping ratio of boron ingot to carbon target was 6% and 12.5%. It can be found that the bond can have a C-B bond signal at the 282.9 eV position, and the spectrum can be found that the sp ² /sp ³ bond ratio is increased by the amount of boron doped, and the sp ² amount tends to rise. When the area ratio of boron to carbon is increased to 12.5%, the ratio of sp ² /sp ³ reaches 10.54 (see Table 2), so it is known that boron The sub-component may combine with the carbon atoms in the graphite state via the action of doping, thereby causing an increase in the amount of sp ² .

Please refer to FIG. 3 , which is a B1s region analysis scan chart of a carbon-coated carbon film for XPS analysis of a method for manufacturing a semiconductor-like diamond-like carbon film according to the present invention. It can be seen from the figure that the coating condition of the present invention is a boron ingot and a carbon target area. The ratio is 0%, 6% and 12.5%, the sputtering power is fixed at 300 W, argon gas is used as the gas excited by the plasma, the diamond-like carbon film is deposited on the high-impedance ruthenium substrate, and the diamond-like carbon film is further X. Analysis by ray photoelectron spectroscopy (XPS); it can be seen from the figure that after the slow scanning of the B1s range of XPS, the range of B1s is between 186 eV and 206 eV, and the spectral results of the B1s range are roughly shown to have doping conditions. The boron-containing diamond carbon film does have a boron signal therein, and as the doping ratio increases, the boron signal also has an increasing tendency, which also means that the boron atom is successfully doped into the diamond-like film.

The method for manufacturing the semiconductor-like diamond-like carbon film provided by the invention has the following advantages when compared with other conventional techniques: 1. The invention uses a magnetron sputtering method with high parameter stability and low risk, Solid stone The ink target and the boron ingot form a composite target for sputtering, and the boron ingot is embedded in the graphite target, and the diamond-like carbon film is simultaneously deposited by the common sputtering method, and the doping action of the boron element is simultaneously performed. The p-type semiconductor diamond-like carbon film and high carrier concentration are achieved.

2. The invention can solve the bottleneck of the current semiconductor material. Under the nanometer scale, the semiconductor carrier concentration, carrier mobility and heat dissipation performance can be solved by the semiconductor-like carbon film.

3. The semiconductor diamond-like carbon film of the present invention can be applied to semiconductor devices and components such as solar cells, semiconductor components, wires and electrodes of electronic components.

The above description is intended to be illustrative of a possible embodiment of the invention, and is not intended to limit the scope of the invention. In the scope of patents.

To sum up, this case is not only innovative in terms of technical thinking, but also able to enhance the above-mentioned multiple functions compared with conventional articles. It should be submitted in accordance with the law in accordance with the statutory invention patents that fully meet the novelty and progressiveness, and you are requested to approve this article. Invention patent application, in order to invent invention, to the sense of virtue.

1‧‧‧Composite targets

11‧‧‧ graphite

12‧‧‧boron tablets

2‧‧‧ copper plate

FIG. 1A and FIG. 1B are structural diagrams of composite targets of a method for manufacturing a semiconductor-like diamond-like carbon film according to the present invention; FIG. 2 is a C1s of a carbon-coated carbon film for XPS analysis of a method for manufacturing a semiconductor-like diamond-like carbon film according to the present invention; The area analysis scan chart; and FIG. 3 is a B1s area analysis scan chart of the carbon-coated carbon film of the XPS analysis method for manufacturing the semiconductor-type diamond-like carbon film of the present invention.

1‧‧‧Composite targets

11‧‧‧ graphite

12‧‧‧boron tablets

2‧‧‧ copper plate

Claims (13)

A method for manufacturing a semiconductor-like diamond-like carbon film is to fabricate a semiconductor-like diamond-like carbon film on a substrate. The manufacturing method is a composite target composed of a carbon target and a boron ingot, and is magnetron sputtered. And with annealing treatment, the p-type semiconductor nature diamond-like carbon film process is carried out, the ratio of boron doping sp ² /sp ^{3 of the process} reaches 2.61~10.54, and the carrier concentration is raised to 2.4×10 ¹⁶ ~1.3×10 ¹⁸ cm ^{- 3} . The method for producing a semiconductor-like diamond-like carbon film according to claim 1, wherein the boron ingot is composed of a boron-containing compound such as boron, boron carbide, boron trioxide or boron nitride. The method for manufacturing a semiconductor-like diamond-like carbon film according to the second aspect of the invention, wherein the boron element compound may be doped with a carbon-based film such as boron (B), lithium (Li) or bismuth (Be). Replace. The method for producing a semiconductor-like diamond-like carbon film according to claim 1, wherein the composite target is embedded in a graphite target or a carbon target from a boron ingot. The method for producing a semiconductor-like diamond-like carbon film according to claim 1, wherein the boron ingot may be embedded in a graphite target or a carbon target in a circular, rectangular or arbitrary shape. The method for producing a semiconductor-like diamond-like carbon film according to claim 1, wherein the filler of the boron ingot is between 0.1% and 40% of the total target area. The method for producing a semiconductor-like diamond-like carbon film according to claim 1, wherein the filler of the boron ingot is between 0.1% and 60% by volume of the total target. A method for producing a semiconductor-like diamond-like carbon film according to claim 1, wherein The area of the boron ingot and the thickness of the thin film deposition all affect the properties of the semiconductor diamond-like carbon film. The method for manufacturing a semiconductor-like diamond-like carbon film according to claim 1, wherein the composite target can be used as a support under the copper plate. The method for manufacturing a semiconductor-like diamond-like carbon film according to claim 1, wherein the substrate of the carbon-deposited carbon film of the physical vapor deposition semiconductor property has a temperature of 250 ° C or more and a physical gas phase of 800 ° C or less. Deposition. The method of manufacturing a semiconductor-like diamond-like carbon film according to claim 1, wherein the final step of the manufacturing method comprises a heat treatment process. The method for manufacturing a semiconductor-like diamond-like carbon film according to claim 1, wherein the magnetron sputtering method has a sputtering power of 300 W. The method for producing a semiconductor-like diamond-like carbon film according to claim 1, wherein the annealing treatment temperature is 500 °C.