TWI358092B - Method for making thin film transistor - Google Patents

Description

100 years.11.23月23日梭正替^页1358092 VI. Description of the invention: [Technical field of invention] [0001] The present invention relates to a method for preparing a thin film transistor, and more particularly to a film based on a carbon nanotube A method of preparing a crystal. [Prior Art] _2] Thin Film Silicon Transistor (TFT) is a key electronic component in modern microelectronics technology and has been widely used in flat panel displays and other fields. The thin film transistor mainly comprises a gate, an insulating layer, a semiconductor layer 'source and a drain ◊, wherein the source and the gate are spaced apart from each other and electrically connected to the semiconductor layer, and the gate passes through the insulating layer and the semiconductor layer and the source and the drain Space insulation setting. The semiconductor layer is located in a region between the source and the drain to form a channel region. The gate, source and drain of the thin film transistor are each composed of a conductive material, which is typically a metal or an alloy. When a voltage is applied to the gate, the channel region in the semiconductor layer spaced apart from the gate through the insulating layer accumulates between the carrier's when the carrier accumulates to a certain extent and the source/drain is electrically connected to the semiconductor layer. It will conduct, so that current flows from the source to the pole. In practical applications, the requirement for thin film transistors is expected to result in a larger switching current ratio. Factors affecting the above-mentioned switching current ratio Except for the preparation process of the thin film transistor, the carrier mobility of the semiconductor material in the thin film transistor semiconductor layer is one of the most important factors affecting the switching current ratio. [〇〇〇3] In the prior art, a material for forming a semiconductor layer in a thin film transistor is an amorphous germanium, a polycrystalline germanium or an organic semiconductor polymer (R. E. I.

Schropp, B. Stannowski, J. K. Rath, New challenges in thin film transistor research, 097119104 Form No. A0101 Page 4 of 29 1003436459-0 1358092 100 years. 11. Month 23 曰 Shuttle §«

Journal of Non-Crystalline Solids, 299-302, 1 304-1310 (2002)). The preparation technique of the amorphous germanium thin film transistor with amorphous germanium as the semiconductor layer is relatively mature, but in the amorphous germanium thin film transistor, since the semiconductor layer usually contains a large number of dangling bonds, the mobility of the carrier is low. , resulting in a slower response of the thin film transistor. A thin film transistor in which polycrystalline germanium is used as a semiconductor layer has a high carrier mobility with respect to a thin film transistor in which amorphous germanium is used as a semiconductor layer, so that the response speed is also fast. However, the low-temperature preparation of polycrystalline germanium thin film transistors is relatively high, the method is complicated, the preparation of large-area thin films is difficult, and the off-state current of polycrystalline germanium thin film transistors is large. Compared with the above-mentioned conventional inorganic thin film transistor, the organic thin film transistor using an organic semiconductor as a semiconductor layer has the advantages of low cost and low preparation temperature, and the organic thin film transistor has high flexibility. However, since the organic semiconductor polymer is mostly jump-conducting at normal temperature, it exhibits high resistivity and low carrier mobility, making the response speed of the organic thin film transistor slow. [0004] Nano carbon tubes have excellent mechanical and electrical properties. Moreover, the carbon nanotubes may exhibit metallic or semi-conducting properties as the nanocarbon tube spirals. Semiconducting carbon nanotubes have a high carrier mobility (typically up to 1 000~1 500 cm2V_1s_1) and are ideal for the preparation of transistors. It has been reported in the prior art to use a semiconducting carbon nanotube-forming carbon nanotube layer as a semiconductor layer of a thin film transistor. The preparation method of the above-mentioned thin film transistor using the carbon nanotube layer as the semiconductor layer mainly comprises the following steps: dispersing the carbon nanotube powder in an organic solvent; mixing the carbon nanotube with the organic solvent by inkjet printing The liquid is printed on the insulating substrate, and after the organic solvent is volatilized, on the predetermined position of the insulating substrate, 097119104, Form No. A0101, Page 5 of 29, 1003436459-0 1358092, 100. November, Zuo Risuo is a substitute for the Θ a carbon nanotube layer; forming a source and a drain on the carbon nanotube layer by depositing and etching a metal thin film; depositing a layer of tantalum nitride on the carbon nanotube layer to form an insulating layer; and depositing on the insulating layer A metal film forms a gate. However, in the above method, the carbon nanotubes need to be dispersed by an organic solvent, the carbon nanotubes are easily agglomerated, and the organic solvent used for dispersion tends to remain in the carbon nanotube layer, affecting the performance of the thin film transistor. In addition, the carbon nanotube layer bonded by the organic solvent has a loose structure and poor flexibility, which is disadvantageous for preparing a flexible thin film transistor.

In view of the above, it is necessary to provide a method for preparing a thin film transistor which is simple in method and suitable for mass production at low cost. SUMMARY OF THE INVENTION [0006] A method for preparing a thin film transistor includes the steps of: providing a growth substrate; forming a catalyst layer uniformly on the surface of the growth substrate; heating the growth substrate on which the catalyst layer is formed in a protective gas atmosphere, The carbon source gas and the carrier gas are controlled to control the volume ratio of the carrier gas to the carbon source gas to be about 100:1 to 100:10, and a single-walled carbon nanotube layer is grown on the surface of the growth substrate; the source and the source are formed at intervals. a pole, and electrically connecting the source and the drain to the carbon nanotube layer; forming an insulating layer on the surface of the carbon nanotube layer; and forming a gate on the surface of the insulating layer to obtain a film Transistor. [0007] Compared with the prior art, the method for preparing a thin film transistor using a directly grown disordered carbon nanotube layer as a semiconductor layer provided by the embodiments of the present technical solution has the following advantages: First, the technical solution is adopted. Directly growing a pure single-walled semiconducting carbon nanotube layer as a semiconductor layer of a thin film transistor, the method of forming such a semiconductor layer is simpler than the method of forming a thin film transistor semiconductor layer by the inkjet printing method of the prior art, without using 097119104 Form No. 1010101 Page 6 of 29 Page 1003436459-0 1358092

100 years, 11th, 23rd, nuclear replacement page The step of dispersing the carbon nanotubes in an organic solvent. The obtained carbon nanotube film has uniform distribution of carbon nanotubes and high purity, which can avoid the agglomeration of the carbon nanotubes in the carbon nanotube layer formed in the prior art, and thus the distribution is uneven, and the carbon nanotubes are distributed. The problem of residual organic solvents in the layer. By properly controlling the ratio of the carbon source gas to the shielding gas, the radius of the obtained carbon nanotube can be controlled to obtain a semiconducting carbon nanotube. The semiconducting carbon nanotube has a high carrier mobility, and as a semiconductor layer, the thin film transistor has a large carrier mobility and a fast response speed. Thirdly, by controlling the growth conditions, the carbon nanotubes in the obtained carbon nanotube layer are disordered and intertwined, so the carbon nanotube layer has good toughness and mechanical strength, so the disordered arrangement of the naphthalene is adopted. As the semiconductor layer, the carbon nanotube layer can correspondingly improve the flexibility of the thin film transistor and the thin film transistor array. [Embodiment] Hereinafter, a method of preparing a thin film transistor provided by an embodiment of the present technical solution will be described in detail with reference to the accompanying drawings. Referring to FIG. 1 and FIG. 2, a first embodiment of the present invention provides a method for fabricating a top gate type thin film transistor 10, which mainly includes the following steps: [0010] Step 1: A growth substrate 110 is provided. [0011] The growth substrate 110 is a high temperature resistant insulating substrate, and the material thereof is not limited to 'ensure that its melting point is higher than the growth temperature of the carbon nanotubes and insulation. In addition, the material of the growth substrate 110 may also be selected from the material of the substrate in a large-scale integrated circuit. The growth substrate 110 is not limited in shape and may have any shape such as a square shape, a circular shape, or the like. The size of the growth substrate 110 is not limited, and may be determined according to actual conditions. The growth substrate 110 has a flat surface. Specifically, the growth substrate 110 may be selected from P-type or N-type sulfhydryl 097119104. Form No. A0101 Page 7 of 29 1003436459-0 1358092 100 years. 11·Month 2.3 Revisions (3) Bottom, oxide layer formed A germanium substrate, a transparent quartz substrate, or a transparent quartz substrate formed with an oxide layer. This embodiment is preferably a crucible substrate formed with an oxide layer. The oxide layer may be a hafnium oxide layer having a diameter of 4 inches. [0012] Step 2: uniformly forming a catalyst layer on the surface of the growth substrate 110. [0013] In the present technical solution, a catalyst layer is uniformly deposited on the surface of the growth substrate 110 by a physical deposition method such as electron beam evaporation deposition. The catalyst layer is a metal layer. The material of the above catalyst layer can be selected from iron (Fe), Ming

(Co), nickel (Ni), magnesium (Mg) or their alloys. The thickness of the catalyst layer is from several nanometers to several hundred nanometers. [0014] The technical solution is selected to use an iron metal layer as a catalyst layer. Specifically, an iron metal layer is deposited by electron beam evaporation on the growth substrate 110 described above. 1〜3纳米。 The thickness of the iron metal layer is 0. 1~3 nm. The above ultrathin catalyst layer is advantageous for the growth of single-walled carbon nanotubes. [0015] Step 3: The growth substrate 110 formed with the catalyst layer is placed in a reaction furnace, heated to 500 to 740 ° C under a protective gas atmosphere, and a carrier gas and a carbon source gas are introduced to control the carrier gas and the carbon source. The volume ratio of gas is about 100:1 to 100:10, and a disordered single-walled carbon nanotube layer 140 is grown as a semiconductor layer of the thin film transistor 10. [0016] Step 3 specifically includes the following steps: first, placing the growth substrate 110 formed with the catalyst layer in the reaction furnace; secondly, introducing a shielding gas into the reaction furnace and heating the growth substrate 110 to 500 having the catalyst layer formed thereon ~740 °C; Finally, the carbon source gas is introduced into the reaction furnace to react with the carrier gas for about 5 to 30 minutes. Wherein, the flow rate of the carbon source gas is about 5 to 50 seem, preferably 097119104. Form No. A0101 Page 8 of 29 1003436459-0 1358092 In November of the 100th, the left replacement page is 20sccm. The reduction in carrier gas is approximately 500 sccra. As the carbon source gas, a chemically active hydrocarbon such as acetylene, ethylene, decane or carbon monoxide may be used, and acetylene is preferable. The carrier gas is hydrogen. The shielding gas is nitrogen or an inert gas. [0017] The number of tubes of the carbon nanotubes grown by the above step three and the carrier gas and carbon source

The proportion of gas is related. By controlling the volume ratio of the carrier gas to the carbon source gas to be in the range of 100:1 to 100:10, the carbon nanotubes in the grown carbon nanotube layer 140 can be controlled to be single-walled carbon nanotubes. 5纳米之间之间之间之间。 The diameter of the carbon nanotubes between 0.5 nm to 10 nm. The carbon nanotubes grown in this example had a diameter of 2 nm. 5纳米〜100微米。 The thickness of the carbon nanotube layer 140 is 0. 5 nanometers ~ 100 microns. As shown in FIG. 3, the carbon nanotube layer 140 includes a plurality of carbon nanotube layers 140 containing semiconductor carbon nanotubes which are disordered and intertwined and grown. The carbon nanotube layer 140 contains substantially no impurities such as amorphous carbon or residual catalyst metal particles, etc., by controlling the growth conditions as described above. The proportion of semiconducting carbon nanotubes in the carbon nanotube layer 140 - ^ accounts for 2/3 of the total mass of the carbon nanotubes.

[0019] It can be understood that, because the growth temperature of the above-mentioned carbon nanotubes is relatively high, the material of the above-mentioned growth substrate 110 must be selected from a hard material having high temperature resistance, thereby limiting the selection of the substrate material. In order to enable the thin film transistor 10 to adopt a wider base material, especially a flexible base material, to form a flexible thin film transistor 10, after the carbon nanotube layer 140 is grown, the transfer step can be further performed by a transfer step. The carbon nanotube layer 140 is transferred to the flexible substrate. [0020] Specifically, the transfer step includes the following steps: First, provide an insulation 097119104 Form No. A0101 Page 9. Total 29 Page 1003436459-0 1358092 [0021] 0022] [0023] 097119104 1100. November 23, the shuttle is replaced by a (3) page substrate, and secondly, the growth substrate 11 formed with the carbon nanotube layer 14〇 is folded over the insulating substrate to make the carbon nanotube layer The surface of the i4〇 is in contact with the surface of the insulating substrate to form a three-layer structure including a growth substrate 11〇, a carbon nanotube layer 140 and an insulating substrate from top to bottom; again, the three-layer structure is hot-pressed, and finally, removed. The substrate 110 is grown such that the above-described carbon nanotube layer 140 is adhered to the surface of the insulating substrate. The material of the insulating substrate is a flexible material such as a plastic or a resin material. In the present embodiment, the insulating substrate is a PET film, and the warming time of the hot pressing depends on the material type of the insulating substrate. When the material of the insulating substrate is a plastic or a resin, the hot pressing temperature is 50 to 2 Torr (rc, and the door is 5 to 30 minutes at the time of hot pressing. The disordered carbon nanotube layer 丨 4〇 grown by the present embodiment) The carbon nanotubes are very pure, and because the specific surface area of the carbon nanotubes itself is very large, the carbon nanotube layer 14 has a strong viscosity. Therefore, the growth substrate of the carbon nanotube layer 14D is used. When the 11Q is buckled on the insulating substrate, the carbon nanotube layer 140 can be adhered to the surface of the insulating substrate. By the ripe pressing step, the nano tube is tightly bonded to the surface of the insulating substrate, thereby easily and growing. The substrate 110 is separated. Step 4: A source 151 and a drain 152 are formed at intervals, and the original 151 and the drain 152 are electrically connected to the carbon nanotube layer 14 。. "The source 151 and the drain are extremely The material of 152 should have better conductivity. Specifically, the material of the source 151 and the drain 152 may be gold 厶 ' σ gold ', tin oxide (ITO), antimony tin oxide (AT 〇), and conductive. Conductive materials such as silver paste, electropolymer, and carbon nanotube film. According to the material forming the source and the drain 152 Depending on the type, the source 151 and the gate 152 can be formed by different methods. Specifically, when the source 151 and the _ _ form number A0101 page 1 / page 29 of 1 〇〇 3436459-〇 1358092

[loo^llj 23B When the material is metal, alloy, ITO or AT, the source 151 and the drain 152 can be formed by vapor deposition, sputtering, deposition, masking, and etching. When the material of the source 151 and the drain 152 is a conductive silver paste, a conductive polymer or a nano-carbon film, the conductive silver paste or the carbon nanotube film can be printed or directly adhered. The source 151 and the drain 152 are formed by coating or adhering to the surface of the growth substrate 110 / insulating substrate or the carbon nanotube layer 14 . Generally, the thickness of the source 151 and the drain 152 is 0.5 nm to 100 μm, and the distance between the source 151 and the drain 152 is 1 to 1 μm. [0024] In this embodiment, The source 151 and the drain 152 are made of metal. The above step 4 can be carried out in two ways. The first method specifically includes the following steps: first, uniformly coating a layer of photoresist on the surface of the carbon nanotube layer 140; secondly, forming a source 151 and a drain on the photoresist by photolithography such as exposure and development. The 152 region 'exposes the carbon nanotube layer 140 in the source 151 and the drain 152 region; again, the photoresist, the source 151 is deposited by vacuum evaporation, magnetron sputtering or electron beam evaporation deposition. And depositing a metal layer on the surface of the 152· pole 152 region, preferably a metal layer, or a metal layer; and finally, removing the photoresist and the metal layer thereon by an organic solvent such as acetone, thereby forming a carbon nanotube layer 140. Source 151 and drain 152 on top. The second method specifically includes the following steps: first, depositing a metal layer on the surface of the carbon nanotube layer 140; secondly, coating a surface of the metal layer with a photoresist; again, removing the source by photolithography such as exposure and development The photoresist in the region of the pole 151 and the region outside the gate 152; finally, the metal layer outside the region of the source 151 and the region of the drain 152 is removed by electric pad etching or the like, and the source 151 region and the germanium are removed by an organic solvent such as acetone. Pole 152 area 097119104. Form No. A0101 No. 11 1/29 pages 1003436459-0 1358092 100 years. On November 23rd, the photoresist was modified to obtain the source formed on the carbon nanotube layer 140. 151 and bungee 152. In this embodiment, the source 151 and the drain 152 have a thickness of 1 μm, and the distance between the source 151 and the drain 152 is 50 μm.

[0025] It can be understood that, in order to obtain the carbon nanotube layer 140 having better semiconductivity, after forming the source 151 and the drain 152, the metal nano-deposited in the carbon nanotube layer 140 may be further included. The steps of the carbon tube. Specifically, the method includes the following steps: first, providing an external power supply, and secondly, connecting the positive and negative poles of the external power source to the source 151 and the drain 152; finally, applying a large voltage across the source 151 and the drain 152 through the external power source. The metallic carbon nanotube is heated and ablated to obtain a semiconducting carbon nanotube layer 140. In addition, the above method of removing the metallic carbon nanotubes in the carbon nanotube layer 140 may also use hydrogen plasma, microwave, terahertz (THz), infrared (IR), ultraviolet (UV) or visible light (Vis). The carbon nanotube layer 140 is irradiated, and the metallic carbon nanotube is heated and ablated to obtain a semiconducting carbon nanotube layer 140. [0027] Step 5: forming an insulating layer 130 on the carbon nanotube layer 140. [0028] The material of the insulating layer 130 may be a hard material such as tantalum nitride or tantalum oxide or a flexible material such as benzocyclobutene (BCB), polyester or acrylic resin. The insulating layer 130 may be formed by different methods depending on the kind of the material of the insulating layer 130. Specifically, when the material of the insulating layer 130 is tantalum nitride or hafnium oxide, the insulating layer 130 may be formed by a deposition method. When the material of the insulating layer 130 is benzocyclobutene (BCB), polyester or acrylic resin, the insulating layer 130 can be formed by a printing coating method. In general, 097119104 Form No. A0101 Page 12 of 29 1003436459-0 1358092

.100. November 2, 3, Revision Replacement Page The thickness of the insulating layer 130 is from 0.5 nm to 100 μm. [0029] In the present embodiment, a tantalum nitride insulating layer 130 is formed by a deposition method such as plasma chemical vapor deposition to cover the carbon nanotube layer 140 and the source 151 and the drain formed on the carbon nanotube layer 140. 152 surface. The insulating layer 130 has a thickness of about 1 micrometer. [0030] It can be understood that, depending on the different applications of the thin film transistor 10, a portion of the source 151 and the drain 152 may be exposed to the insulating layer by photolithography or etching similar to the formation of the source 151 and the drain 152. 130 outside. [0031] Step 6: forming a gate 120 on the surface of the insulating layer 130 to obtain a thin film transistor 10. [0032] The material of the gate 120 should have good electrical conductivity. Specifically, the material of the gate 120 may be a conductive material such as a metal, an alloy, a tantalum, a tantalum, a conductive silver paste, a conductive polymer, or a carbon nanotube film. The metal or alloy material may be aluminum, copper, tungsten, molybdenum, gold or alloys thereof. Specifically, when the material of the gate 120 is metal, alloy, ΙΤ0 or ΑΤΟ, the gate 120 may be formed by evaporation, sputtering, deposition, masking, etching, or the like. When the material of the gate 120 is a conductive silver paste, a conductive polymer or a carbon nanotube film, the gate 120 can be formed by direct adhesion or printing. 5纳米至100微米。 Generally, the thickness of the gate 120 is 0. 5 nm ~ 100 microns. In the embodiment of the present invention, a conductive film is formed as the gate 120 on the surface of the insulating layer 130 and at a position opposite to the semiconductor layer by a method similar to the formation of the source electrode 151 and the drain electrode 152. The gate 120 is electrically insulated from the semiconductor layer by an insulating layer 130. In the embodiment of the technical solution, the material of the gate 120 is 097119104, the form number is Α0101, and the third page is 1003436459-0 1358092. On the 11th, 23rd, the nuclear material is aluminum, and the thickness of the gate 120 is It is about 1 micron. Referring to FIG. 4 and FIG. 5, a second embodiment of the present invention provides a method for fabricating a bottom gate type thin film transistor 20, which is substantially the same as the method for preparing the thin film transistor 10 of the first embodiment. The main difference is that the thin film transistor 20 formed in this embodiment is a bottom gate type structure. The second embodiment of the present invention provides a method for preparing a thin film transistor 20 comprising the following steps: [0035] [0040] [0041] Step 1: Providing a growth substrate. Step 2: uniformly forming a catalyst layer on the surface of the growth substrate. Step 3: placing the growth substrate formed with the catalyst layer in a reaction furnace, heating to 500-740 ° C under a protective gas atmosphere, introducing a carrier gas and a carbon source gas, and controlling the volume ratio of the carrier gas to the carbon source gas. In the range of 100:1 to 100:10, a disordered single-walled carbon nanotube layer 240 is grown. Step 4: Provide an insulating substrate 210. Step 5: Form a gate 220 on the surface of the insulating substrate 210. Step 6: Form an insulating layer 230 to cover the gate 220. Step 7: Transfer the carbon nanotube layer 240 to the surface of the insulating layer 230.

[0042] The transfer step specifically includes the following steps: first, the growth substrate on which the carbon nanotube layer 240 is formed is inverted on the insulating substrate 210 so that the surface of the carbon nanotube layer 240 is in contact with the surface of the insulating layer 230, thereby Forming a three-layer structure including a growth substrate, a carbon nanotube layer 240, and an insulating substrate 210 in order from top to bottom; again, hot pressing the three-layer structure; finally, removing the growth substrate to thereby make the carbon nanotube layer 240 adheres to the surface of the insulating layer. 097119104 Form No. A0101 Page 14 of 29 1003436459-0 1358092 10 0. November 2 3 Nuclear Replacement Page [0043] When the growth substrate formed with the carbon nanotube layer 240 is inverted to the insulation On the substrate 210, it is ensured that the surface of the carbon nanotube layer 240 is adhered to the surface of the insulating layer 230, so that the carbon nanotube layer 240 is adhered to the insulating layer 230. [0044] Step 8: forming a source 251 and a drain 252 at intervals, and electrically connecting the source 251 and the drain 252 to the carbon nanotube layer 240. [0045] The source electrode 251, the drain electrode 252, the gate electrode 220, and the insulating layer 230 may be formed in the same manner as in the first embodiment. [0046] Referring to FIG. 6, a third embodiment of the present technical solution provides a method for preparing a thin film transistor, which is basically the same as the method for preparing the thin film transistor 10 of the first embodiment. The main difference is that this embodiment forms a plurality of thin film transistors on the same insulating substrate to form a thin film transistor array. The method for preparing the thin film transistor of the embodiment specifically includes the following steps: [0047] Step 1: providing a growth substrate. [0048] Step 2: uniformly lining the surface of the growth substrate to form at least one catalyzed layer. [0049] Specifically, when a plurality of catalyst layers are formed, a catalyst layer of a large area is formed prior to the surface of the growth substrate, and the catalyst layer is patterned by mask etching or laser cutting, etc., thereby forming a thin film. A plurality of catalyst layers are formed at different positions of the transistor. [0050] Step 3: placing the growth substrate formed with at least one catalyst layer in a reaction furnace, heating to 500-740 ° C under a protective gas atmosphere, introducing a carrier gas and a carbon source gas, and controlling the carrier gas and the carbon source. The volume ratio of gas is in the range of about 100:1 to 100:10, and a plurality of disordered single-walled carbon nanotube layers are formed on the surface of the growth substrate. 097119104 Form No. A0101 Page 15 of 29 1003436459-0 1358092 100. November 23rd Nuclear Replacement Page [0051] When a catalyst layer is formed in the second step, the catalyst layer has a large area. After the carbon nanotube layer is grown on the large-area catalyst layer in step three, the carbon nanotube layer may be further processed by a laser cutting or mask etching method, thereby obtaining a plurality of carbon nanotube tubes. A layer is formed on the surface of the growth substrate. [0052] When a plurality of catalyst layers are formed in the second step, a plurality of carbon nanotube layers may be directly grown on the plurality of catalyst layers in the third step, thereby eliminating the need to cut or engrave the carbon nanotube layers. .

[0053] It can be understood that, similar to the preparation method of the thin film transistor 10 of the first embodiment, since the plurality of carbon nanotube layers have a large viscosity, the embodiment can pass the plurality of nanocarbons by a transfer step. The tube layer is transferred onto a flexible insulating substrate to form a plurality of flexible thin film transistors. [0054] Step 4: forming a plurality of sources and a plurality of drains at intervals, and electrically connecting each of the carbon nanotube layers to a source and a drain.

[0055] Similar to the method of forming the source and the drain of the thin film transistor 10 of the first embodiment, in this embodiment, a metal thin film may be deposited on the surface of the entire growth substrate on which the plurality of carbon nanotube layers are formed, and then The metal thin film is patterned by etching or the like to form a plurality of sources and a plurality of drains at a predetermined position. The material of the source and the drain may also be an ITO film, a tantalum film, a conductive polymer film, a conductive silver paste or a carbon nanotube film. [0056] Step 5: forming an insulating layer on each of the carbon nanotube layers. Similar to the method for preparing the insulating layer in the thin film transistor 10 of the first embodiment, a tantalum nitride film may be deposited on the surface of the entire growth substrate, and the tantalum nitride film may be patterned by etching or the like to be predetermined. Position last 097119104 Form No. 1010101 No., 16 pages/Total 29 pages 1003436459-0 1358.092 100 years. November h. Shuttle is replacing the page to form a plurality of insulation layers. The material of the above insulating layer may be a hard material such as cerium oxide or a flexible material such as benzocyclobutene (BCB), polyester or acrylic resin. [0057] Step 6: forming a gate on the surface of each insulating layer to obtain a thin film transistor array including a plurality of thin film transistors. [0058] It will be understood that a thin film transistor array can also be formed by a method similar to that of the second embodiment, which specifically includes the following steps: [0059] Step 1: A growth substrate is provided. Step 2: uniformly forming a catalyst layer on the surface of the growth substrate. [0061] Step 3: The growth substrate formed with the catalyst layer is placed in a reaction furnace, heated to 500-740 ° C under a protective gas atmosphere, and a carrier gas and a carbon source gas are introduced to control the carrier gas and the carbon source gas. In a volume ratio of about 100:1 to 100:10, a disordered single-walled carbon nanotube layer is grown. [0062] Step 4: Providing an insulating substrate. • [0063] Step 5: Forming a plurality of gates on the surface of the insulating substrate. [0064] Step 6: forming at least one insulating layer covering the plurality of gates. [0065] Step 7: transferring the carbon nanotube layer to the surface of the insulating layer, patterning the carbon nanotube layer to form a plurality of carbon nanotube layers, the plurality of carbon nanotube layers and the above The plurality of gates are opposite and insulated by an insulating layer. [0066] Step 8: forming a plurality of sources and a plurality of drains at intervals, and electrically connecting each of the carbon nanotube layers to a source and a drain. [0067] The method for preparing a thin film transistor provided by the embodiment of the present technical solution has the following advantages: 097119104 Form No. A0101 Page 17/Total 29 pages. 1003436459-0 100 years.11. According to the technical solution, a pure single-walled, half-walled, V-shaped carbon nanotube layer is directly used as a semiconductor layer of a thin film transistor, and the method of forming the half-V body layer forms a thin film electricity TM by the inkjet printing method in the prior art. The method of the bulk semiconductor layer is simple, and it is not necessary to carry out the step of dispersing the carbon in the organic solvent. The obtained carbon nanotube film has uniform distribution of carbon nanotubes and high purity, which avoids the agglomeration of nanocarbon camps in the nano-carbon B layer formed in the prior art, and thus the distribution is uneven and the carbon nanotube layer is distributed. The problem of residual organic solvents in the medium. Second, by controlling the ratio of carbon source gas to the ratio of the gas to the gas, the radius of the obtained carbon nanotube can be controlled to obtain a semiconducting carbon nanotube. The semiconducting carbon nanotube has a high carrier mobility, and as the semiconductor layer, the thin film transistor can have a relatively large plant mobility and a fast response speed. Third, by controlling the growth conditions, the carbon nanotubes in the carbon nanotube layer are disordered and intertwined.

Therefore, the carbon nanotube layer has good toughness and mechanical strength, so the disordered arrangement of the carbon nanotube layer as the semiconductor layer can correspondingly improve the flexibility of the thin film transistor and the thin film transistor array. Fourth, since the carbon nanotube layer provided in the embodiment has a large viscosity and can adhere to the surface of the other substrate, the transfer process can be used to transfer the carbon nanotube layer to other substrates. The material of the substrate can be selected from a flexible material that is not resistant to high temperatures, and is advantageous for preparing a flexible thin germanium transistor. [0068] In summary, the invention has been in compliance with the requirements of the invention patent, and the patent application is filed according to law. However, the above description is only a preferred embodiment of the present invention, and it is not possible to limit the scope of the patent application of the present invention. Equivalent modifications or variations made by those skilled in the art in light of the spirit of the invention are intended to be included within the scope of the following claims. 097119104 Form No. A0101 Page 18 of 29 1003436459-0 1358092 [0069] [0072] [0072]

[0075] [0075]

[0078] [0078] [0088] [0081] 100 years. 11. The first day of the film is replaced by a simple description of the drawings. FIG. 1 is a preparation of the film transistor of the first embodiment of the present technical solution. Flow chart of the method. Fig. 2 is a flow chart showing the preparation process of the thin film transistor of the first embodiment of the present technical solution. Fig. 3 is a scanning electron micrograph of a carbon nanotube layer in a thin film transistor of the first embodiment of the present technical solution. Fig. 4 is a flow chart showing a method of preparing a thin film transistor of a second embodiment of the present technical solution. Fig. 5 is a flow chart showing the preparation process of the thin film transistor of the second embodiment of the present technical solution. Fig. 6 is a flow chart showing a method of compiling a thin film transistor of a third embodiment of the present technical solution. [Main component symbol description] Thin film transistor: 10,20 Insulation substrate: 110,210 Gate: 1 20, 220 Insulation: 130,230 Carbon nanotube layer: 140, 240 Source: 1 51, 2 51 汲Pole: 152, 252 097119104 Form No. A0101 Page 19 / Total 29 Page 1003436459-0

Claims (1)

1358092 100 years. November 23rd Nuclear VII. Patent application scope: 1. A method for preparing a thin film transistor, comprising the steps of: providing a growth substrate; forming a catalyst layer uniformly on the surface of the growth substrate; forming a catalyst layer The growth substrate is heated in a protective gas atmosphere, and the carbon source gas and the carrier gas are introduced to control the volume ratio of the carrier gas to the carbon source gas to be about 10 (hl to 100:10), and a single-walled carbon nanotube is grown on the surface of the growth substrate. Floor; Forming a source and a drain, and electrically connecting the source and the drain to the carbon nanotube layer; forming an insulating layer on the surface of the carbon nanotube layer; and surface of the insulating layer A gate is formed to obtain a thin film transistor. 2. The method for preparing a thin film transistor according to claim 1, wherein the carbon nanotube is a semiconducting carbon nanotube, and the diameter of the carbon nanotube is 0.5 nm to 10 nm. Meter. 3. The method for preparing a thin film transistor according to claim 1, wherein the carbon nanotubes in the carbon nanotube layer are disorderly arranged and entangled with each other / 4 as claimed in claim 1 The method for preparing a thin film transistor, wherein the catalyst layer is a metal layer, and the material of the catalyst layer is one of iron, cobalt, magnesium, magnesium or any combination of the above metals, and the thickness of the catalyst layer is 0.1 to 3 nm. 5. The method for preparing a thin film transistor according to claim 1, wherein the heating temperature in the protective gas atmosphere is 500 to 740 ° C, and the reaction time after introducing the carbon source gas and the carrier gas For 5 to 30 minutes. 6. The method for preparing a thin film transistor according to claim 5, which is 097119104, Form No. A0101, Page 20 of 29, 1003436459-0, 1358092, 100.11, Month 23, _for the ¥ page The carbon source gas is acetylene, ethylene, methane or carbon monoxide, the carrier gas is hydrogen, and the shielding gas is nitrogen or an inert gas. 7. The method for preparing a thin film transistor according to claim 1, wherein After forming the carbon nanotube layer on the growth substrate, further comprising the step of transferring the carbon nanotube layer, the transferring step comprising: providing an insulating substrate; and forming a growth substrate having a carbon nanotube layer Folding on the insulating substrate to bring the surface of the carbon nanotube layer into contact with the surface of the insulating substrate, thereby forming a three-layer structure including a growth substrate, a carbon nanotube layer and an insulating substrate; hot pressing the three-layer structure; and removing the growth a substrate such that the carbon nanotube layer adheres to the surface of the insulating substrate. 8. The method of producing a thin film transistor according to claim 7, wherein the insulating substrate is made of a plastic or a resin. 9. The method of producing a thin film transistor according to claim 1, wherein the source and the drain are formed directly on the carbon nanotube layer. 10. The method for preparing a thin film transistor according to claim 1, wherein The step of growing a single-walled carbon nanotube layer further includes a step of removing the metallic carbon nanotubes in the carbon nanotube layer. The method for producing a thin film transistor according to claim 10, wherein the step of removing the metallic carbon nanotube in the carbon nanotube film is performed after forming the source and the drain Specifically, the method comprises: providing an external power source; connecting the positive and negative poles of the external power source to the source and the drain; and applying a voltage of 1 000 volts to the source and the drain by an external power source to make the metallic carbon nanotube Fever and ablate to obtain a semiconducting carbon nanotube layer. 12. The method for preparing a thin film transistor according to the above-mentioned claim, wherein the step of removing the metallic carbon nanotube in the carbon nanotube layer is by hydrogen plasma, microwave, terahertz, Infrared, ultraviolet or visible light illumination 097119104 Form No. A0101 Page 21 of 29 1003436459-0 1358092 13 . 14 . 15 100. November 23 Revision Replacement of the carbon nanotube layer to make metallic carbon nanotubes Burn money. A method for preparing a thin film transistor comprises the steps of: providing a growth substrate; forming a catalyst layer uniformly on the surface of the growth substrate; heating the growth substrate formed with the catalyst layer in a protective gas atmosphere, and introducing a carrier gas and a carbon source gas , controlling the volume ratio of the carrier gas to the carbon source gas to be about 100:1 to 100:10, growing a disordered single-walled carbon nanotube layer; providing an insulating substrate; forming a gate on the surface of the insulating substrate; Forming an insulating layer covering the gate; transferring the carbon nanotube layer to the surface of the insulating layer; and spacing to form a source and a drain, and the source and the drain and the nanocarbon The tube layers are electrically connected to obtain a thin film transistor. A method for preparing a thin film transistor, comprising the steps of: providing a growth substrate; forming at least one catalyst layer uniformly on the surface of the growth substrate; heating the growth substrate formed with at least one catalyst layer in a protective gas atmosphere, introducing a carrier gas and The carbon source gas reacts to control the volume ratio of the carrier gas to the carbon source gas to be about 100:1 to 100:10, forming a plurality of disordered single-walled carbon nanotube layers; forming a plurality of sources and a plurality of drains at intervals And each of the carbon nanotube layers is electrically connected to a source and a drain; an insulating layer is formed on each of the carbon nanotube layers; and a gate is formed on the surface of each of the insulating layers, A plurality of thin film transistors are obtained to form a thin film transistor array. a method for preparing a thin film transistor according to claim 14, wherein 097119104 Form No. A0101 Page 22 of 29 1003436459-0 1358092 In the 100-year, November 2-3 revision replacement page, when a plurality of catalyst layers are formed, the step of forming a plurality of catalyst layers includes: forming a large-area catalyst layer on the surface of the growth substrate, and the large-area catalyst The layers are patterned by mask etching or laser cutting to form a plurality of catalyst layers. The method for producing a thin film transistor according to claim 14, wherein when a catalyst layer is formed, after the carbon nanotube layer is grown on the catalyst layer, further comprising a laser cutting or masking The step of engraving the carbon nanotube layer forms a plurality of carbon nanotube layers. The method for preparing a thin film transistor according to claim 14, wherein after the carbon nanotube layer is grown on the growth substrate, further comprising a step of transferring the carbon nanotube layer, the transfer The method includes: providing an insulating substrate; folding the growth substrate on which the carbon nanotube layer is formed on the insulating substrate; and removing the growth substrate to adhere the carbon nanotube layer to the surface of the insulating substrate. 1003436459-0 097119104 Form NumberΑ0101 Page 23 of 29