A metal oxide semiconductor, thin film transistor and application thereof

Abstract

The present invention discloses a metal oxide semiconductor, which is: in a metal oxide MO-In2O3 semiconductor containing indium, oxides of at least two rare earth elements R and oxides of a rare earth element R' are respectively doped to form In x M y R n R' m O z semiconductor material. By introducing oxides of rare earth elements R and R' into the indium-containing metal oxide, the present invention respectively serves as carrier control and enhances the optical stability. By utilizing the extremely high oxygen bond-breaking energy in the oxide of rare earth element R, the carrier concentration in the semiconductor can be effectively controlled. At the same time, by utilizing the characteristic that the rare earth ion radius is equivalent to the indium ion radius in indium oxide, and the 4f orbital structure in the rare earth element R' ion can form an efficient charge conversion center with the 5s orbital of the indium ion to improve its electrical stability, especially the stability under light. The present invention also provides a thin film transistor and an application based on the metal oxide semiconductor.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor manufacturing, and in particular to materials and device structures used in the production of metal oxide semiconductor thin film transistor backplanes in flat panel displays and detector applications, and specifically to metal oxide semiconductors and thin film transistors and their applications. Background Art

[0002] In the existing metal oxide semiconductor system, indium ions (In 3+ ) Due to its relatively large ionic radius, a higher probability of orbital overlap in multinary metal oxides ensures its efficient carrier transport channel, and its 5s orbital is the main electron transport channel. However, on the one hand, due to the low bond breaking energy of In-O after indium and oxygen form a bond, there are a large number of oxygen vacancy defects in pure indium oxide (In2O3) films. Oxygen vacancies are the main reason for the deterioration of the stability of metal oxide thin film transistors. On the other hand, there are many lattice mismatches in conventional sputtering indium oxide, which makes the carrier mobility of the film low, limiting its application in high-performance thin film transistors. Usually, it is necessary to dope with In 3+ Ga ions with similar numbers 3+ Ions regulate oxygen vacancies. At the same time, in order to ensure the uniformity of the performance of semiconductor devices, the metal oxide semiconductor film needs to maintain an amorphous film structure.

[0003] Since the crystal structure of ZnO is quite different from that of In2O3 and Ga2O3, adding Zn ions in the same amount as In ions into the film can inhibit the crystallization of the material and maintain the amorphous structure of the film. Therefore, IGZO (In:Ga:Zn=1:1:1mol) is the most widely used metal oxide semiconductor material at present.

[0004] However, IGZO also has some problems: 3+ and Zn 2+ The addition of a large amount of ions greatly dilutes In 3+ The concentration of ions decreases, thereby reducing the overlap of the 5s orbitals and lowering the electron mobility.

[0005] In addition, materials such as IGZO have a large number of trap states near the valence band. This results in the generation of photogenerated carriers even when the illumination energy is lower than the bandgap width, resulting in the poor photostability of current metal oxide semiconductors. Summary of the invention

[0006] To overcome the deficiencies of the prior art, the present invention provides a metal oxide semiconductor with relatively high mobility and strong optical stability. It is a new co-doping strategy that utilizes the special 4f electron orbital characteristics of rare earth oxides to achieve relatively high mobility while controlling the carrier concentration in an oxide film with a high In ratio, and obtain a metal oxide semiconductor with strong optical stability.

[0007] The new co-doping strategy of the present invention is to simultaneously introduce oxide materials of two rare earth elements R with different functions and oxide materials of rare earth element R' in an indium-containing metal oxide. Among them, the oxide of rare earth element R is a carrier concentration controller, and the oxide of rare earth element R' is an optical stabilizer, that is, the oxide of rare earth element R' is a charge conversion center, and its principle of action is as follows:

[0008] The carrier concentration controller utilizes the Yb in ytterbium oxide and europium oxide among the oxides of rare earth element R 2+ ions and Eu 2+ ions respectively have completely filled and half-filled 4f electron orbits. Therefore, the divalent ions in the oxide of rare earth element R have lower energy in the oxide compared to trivalent ions. In an oxide semiconductor, when In 3+ ions are substituted for doping, the carrier concentration can be significantly reduced. At the same time, since the bond-breaking enthalpy changes (ΔHf298) of Yb-O and Eu-O are 715.1 kJ / mol and 557.0 kJ / mol respectively, both are much greater than the bond-breaking energy of In-O (360.0 kJ / mol), and thus the oxygen vacancy concentration can be effectively controlled. In summary, combining the above two characteristics, the introduction of the oxide of rare earth element R can effectively control the oxygen vacancies in the oxide semiconductor film in a high In system. Among them, since the ionic radius of Yb 2+ is smaller than that of Eu 2+ ions, it is more conducive to reducing the In-In distance in the oxide semiconductor, and thus can better maintain its good high-mobility characteristics.

[0009] The optical stabilizer utilizes the characteristics that the rare earth ion radii of materials such as praseodymium oxide, terbium oxide, cerium oxide, and dysprosium oxide in the oxide of rare earth element R' are equivalent to the indium ion radius in indium oxide, and the 4f orbital electron structure in the rare earth ions and the 5s orbital of indium ions can form an efficient charge conversion center to improve its electrical stability, especially the stability under light irradiation.

[0010] The second object of the present invention is to provide a thin film transistor comprising the metal oxide semiconductor.

[0011] The third object of the present invention is to provide an application of the thin film transistor.

[0012] The present invention is implemented by adopting the following technical solutions:

[0013] A metal oxide semiconductor, which is: in a metal oxide MO-In2O3 semiconductor containing indium, oxides of at least two rare earth elements R and oxides of rare earth element R' are respectively doped to form In x M y R n R' m O z semiconductor material, where x + y + m + n = 1, 0.4 ≤ x < 0.9999, 0 ≤ y < 0.5, 0.0001 ≤ (m + n) ≤ 0.2, m > 0, n > 0, z > 0.

[0014] That is, the metal oxide semiconductor provided by the present invention is a composite semiconductor based on indium oxide. Through the means of co-doping, two types of rare earth oxides with different functions but complementary effects are introduced. The optional materials for the oxide of rare earth element R are ytterbium oxide and europium oxide. As a carrier concentration controller, the Yb 2+ ions and Eu 2+ ions in ytterbium oxide and europium oxide respectively have completely filled and half-filled 4f electron orbits. Therefore, the divalent ions in the oxide of rare earth element R have lower energy than the trivalent ions in the oxide. In the oxide semiconductor, when substituting In 3+ ions for doping, the carrier concentration can be significantly reduced. At the same time, since the bond-breaking enthalpy changes (ΔHf298) of Yb-O and Eu-O are 715.1 kJ / mol and 557.0 kJ / mol respectively, both are much greater than the bond-breaking energy of In-O (360.0 kJ / mol), and thus the oxygen vacancy concentration can be effectively controlled. Combining the above two characteristics, the introduction of the oxide of rare earth element R can effectively control the oxygen vacancies in the oxide semiconductor thin film in a high-In system. Among them, since the ionic radius of Yb 2+ is smaller than that of Eu 2+ , it is more conducive to reducing the In-In distance in the oxide semiconductor, and thus can better maintain its good high-mobility characteristics.

[0015] Meanwhile, the optional materials for the oxide of rare earth element R' are praseodymium oxide, terbium oxide, cerium oxide, and dysprosium oxide. This material selection utilizes the characteristics of the 4f orbital electron structure in rare earth ions, which can form an efficient charge conversion center with the 5s orbital of indium ions. Under positive bias, the rare earth ions are in a stable low-energy state. Due to the modulation of the Fermi level, the thin film has a relatively high carrier concentration, which can effectively shield the carrier scattering effect caused by this conversion center, thus having no obvious impact on the electrical properties of the device. Under negative bias, the electron orbitals in the 4f of the rare earth element couple with the 5s orbital of indium, and the rare earth ions are in an unstable activated state. On the one hand, it causes an increase in the off-state current of the device, and its scattering effect on carriers is enhanced, resulting in a slight increase in the subthreshold swing of the device; on the other hand, when appropriate light excites photo-generated carriers, the photo-generated electrons will be quickly "captured" by this activated conversion center and recombine with the ionized oxygen vacancies in the form of non-radiative transition through its coupled orbitals, while this activated center returns to the activated state again. Therefore, this conversion center can provide a fast recombination channel for photo-generated carriers, avoiding its impact on the I-V characteristics and stability, and greatly improving the stability of the metal oxide semiconductor device under illumination.

[0016] Furthermore, the oxide of the rare earth element R is a carrier concentration controller; the oxide of the rare earth element R is one or a combination of two materials of ytterbium oxide and europium oxide.

[0017] Furthermore, the oxide of the rare earth element R' is a light stabilizer; the oxide of the rare earth element R' is one or a combination of any two or more materials of praseodymium oxide, terbium oxide, cerium oxide, and dysprosium oxide.

[0018] Furthermore, in the MO, M is one or a combination of any two or more materials of Zn, Ga, Sn, Ge, Sb, Al, Mg, Ti, Zr, Hf, Ta, and W.

[0019] Furthermore, the metal oxide semiconductor is formed into a film by using any one of the methods of physical vapor deposition process, chemical vapor deposition process, atomic layer deposition process, laser deposition process, reactive ion deposition process, and solution method process.

[0020] The second object of the present invention is achieved by the following technical solution:

[0021] A thin film transistor, which includes a gate, an active layer, an insulating layer located between the gate and the active layer, a source electrode and a drain electrode respectively electrically connected to both ends of the active layer, and a spacer layer. It is characterized in that the active layer is the above-mentioned metal oxide semiconductor.

[0022] That is, the present invention also provides a thin film transistor formed by an active layer made of the metal oxide semiconductor. The metal oxide semiconductor is obtained by simultaneously introducing oxides of two rare earth elements R with different functions and oxides of a rare earth element R' into an indium-containing metal oxide. Among them, the oxide of the rare earth element R serves as a carrier concentration controller, and the oxide of the rare earth element R' serves as a light stabilizer, so that it can maintain good high mobility characteristics and improve its electrical stability, especially the stability under light illumination.

[0023] Further, the spacer layer is one of the structures of silicon oxide, silicon nitride, or silicon oxynitride thin films prepared by plasma enhanced chemical vapor deposition or a stacked structure composed of any two or more of them.

[0024] The third object of the present invention is achieved by the following technical solution:

[0025] The application of the thin film transistor in a display panel or a detector.

[0026] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0027] Through a new co-doping strategy, the present invention simultaneously realizes carrier concentration control and achieves good device light stability in an indium-based metal oxide by introducing two rare earth oxide materials with different functions, providing a brand-new idea for the realization of future high-performance metal oxide semiconductor materials.

[0028] The present invention introduces oxides of at least two rare earth elements R and oxides of a rare earth element R' into an indium-containing metal oxide to form a metal oxide semiconductor. The oxide of the rare earth element R serves as a carrier control, and the oxide of the rare earth element R' serves to enhance light stability. The purpose is to effectively control the carrier concentration in the oxide semiconductor by utilizing the extremely high oxygen bond-breaking energy in the oxide of the rare earth element R. At the same time, by using the characteristic that the rare earth ion radius is equivalent to the indium ion radius in indium oxide, and the 4f orbital electron structure in the rare earth element R' ion can form an efficient charge conversion center with the 5s orbital of the indium ion, its electrical stability, especially the stability under light illumination, is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 Schematic diagrams of the thin film transistor structures of Example 13 and Example 14;

[0030] Figure 2 Schematic diagrams of the thin film transistor structures of Example 15, Example 16, and Example 17;

[0031] Figure 3 Schematic diagram of the thin film transistor structure of Example 18;

[0032] Figure 4 Device transfer characteristics and photocurrent characteristics diagrams for Example 13;

[0033] Figure 5 Device transfer characteristics and photocurrent characteristics diagrams for Example 14;

[0034] Figure 6 Device transfer characteristics and photocurrent characteristics diagrams for Example 15;

[0035] Figure 7 Device transfer characteristics and photocurrent characteristics diagrams for Example 16;

[0036] Figure 8 Device transfer characteristics and photocurrent characteristics diagrams for Example 17;

[0037] Figure 9 Device transfer characteristics and photocurrent characteristics diagrams for Example 18.

[0038] In the figures, each reference numeral: 01, substrate; 02, buffer layer; 03, channel layer; 04, insulating layer; 05, gate; 06, spacer layer; 07-1, source electrode; 07-2, drain electrode; 08, etch stop layer. Detailed implementation manners

[0039] Next, in combination with the accompanying drawings and detailed implementation manners, the present invention will be further described. It should be noted that, on the premise of non-conflict, any combination can be formed among the following-described embodiments or technical features to form new embodiments.

[0040] The following are specific embodiments of the present invention. The raw materials, equipment, etc. used in the following embodiments can be obtained by purchasing except for special limitations.

[0041] Example 1: Praseodymium Oxide and Europium Oxide Doped Indium Tin Zinc Oxide Semiconductor Material

[0042] A group of metal oxide semiconductor materials, and this group of metal oxide semiconductor materials is: Praseodymium oxide is doped into indium tin zinc oxide (InSnZnO) as a charge conversion center, and europium oxide is doped as a carrier control agent to form a semiconductor material of praseodymium oxide and europium oxide co-doped indium tin zinc oxide (Pr-Eu:InSnZnO).

[0043] Among them, MO is tin zinc oxide, In:Sn:Zn = 3:1:1 mol, marked as In(3)Sn(1)Zn(1); In x (SnZn) y Eu n Pr m O zwhere x = 0.5, y = 0.3333, m = 0.05, and n = 0.1167. However, it is not limited to the above ratios. In some other embodiments, x = 0.53, y = 0.353, m = 0.05, n = 0.067, or x = 0.56, y = 0.373, m = 0.05, n = 0.017, or x = 0.58, y = 0.387, m = 0.03, n = 0.003, which will not be elaborated here.

[0044] Example 2: Praseodymium Oxide and Ytterbium Oxide Co-Doped Indium Zinc Titanium Oxide Semiconductor Material

[0045] A group of metal oxide semiconductor materials, which are: Praseodymium oxide is doped into indium zinc titanium oxide (InZnTiO) as a charge conversion center, and ytterbium oxide is doped as a carrier control agent to form a semiconductor material of praseodymium oxide and ytterbium oxide co-doped indium zinc titanium oxide (Pr-Yb:InZnTiO).

[0046] Among them, MO is zinc titanium oxide, In:Zn:Ti = 4:1:0.05 mol, marked as In(4)Zn(1)Ti(0.05); In x (ZnTi) y Yb n Pr m O z where x = 0.75, y = 0.1969, m = 0.0031, and n = 0.05. However, it is not limited to the above ratios. In some other embodiments, x = 0.7, y = 0.1838, m = 0.0662, n = 0.05, or x = 0.65, y = 0.17, m = 0.13, n = 0.05, which will not be elaborated here.

[0047] Example 3: Terbium Oxide and Europium Oxide Co-Doped Indium Gallium Zinc Oxide Semiconductor Material

[0048] A group of metal oxide semiconductor materials, which are: Terbium oxide is doped into indium gallium zinc oxide (InGaZnO) as a charge conversion center, and europium oxide is doped as a carrier control agent to form a semiconductor material of terbium oxide and europium oxide co-doped indium gallium zinc oxide (Tb-Eu:InGaZnO).

[0049] Among them, MO is gallium zinc oxide, In:Ga:Zn = 4:0.5:1 mol, marked as In(4)Ga(0.5)Zn(1); In x (GaZn) y Eu n Tb m O zwhere x = 0.65, y = 0.2438, m = 0.05, and n = 0.0562. However, it is not limited to the above ratios. In some other embodiments, x = 0.55, y = 0.2053, m = 0.05, n = 0.1937, or x = 0.58, y = 0.2175, m = 0.05, n = 0.1525, or x = 0.6, y = 0.225, m = 0.05, n = 0.125, which will not be elaborated here.

[0050] Example 4: Terbium Oxide and Ytterbium Oxide Co-Doped Indium Gallium Zirconium Oxide Semiconductor Material

[0051] A group of metal oxide semiconductor materials, which are: terbium oxide is doped into indium gallium zirconium oxide (InGaZrO) as a charge conversion center, and ytterbium oxide is doped as a carrier control agent to form a semiconductor material of terbium oxide and ytterbium oxide co-doped indium gallium zirconium oxide (Tb-Yb:InGaZrO).

[0052] where MO is gallium zirconium oxide, In:Ga:Zr = 5:1:0.05 mol, labeled as In(5)Ga(1)Zr(0.05); In x (GaZr) y Yb n Tb m O z where x = 0.7, y = 0.147, m = 0.103, and n = 0.05. However, it is not limited to the above ratios. In some other embodiments, x = 0.65, y = 0.1365, m = 0.1635, n = 0.05, or x = 0.63, y = 0.1323, m = 0.1877, n = 0.05, or x = 0.74, y = 0.1554, m = 0.0546, n = 0.05, which will not be elaborated here.

[0053] Example 5: Cerium Oxide and Europium Oxide Co-Doped Indium Zinc Oxide Semiconductor Material

[0054] A group of metal oxide semiconductor materials, which are: cerium oxide is doped into indium zinc oxide (InZnO) as a charge conversion center, and europium oxide is doped as a carrier control agent to form a semiconductor material of cerium oxide and europium oxide co-doped indium zinc oxide (Ce-Eu:InZnO).

[0055] where MO is zinc oxide, In:Zn = 9:1 mol, labeled as In(9)Zn(1); In x Zn y Eu n Ce m O zAmong them, x = 0.68, y = 0.0756, m = 0.1944, n = 0.05. However, it is not limited to the above ratios. In some other embodiments, x = 0.7, y = 0.0778, m = 0.1722, n = 0.05, or x = 0.75, y = 0.0833, m = 0.1167, n = 0.05, or x = 0.8, y = 0.0889, m = 0.0611, n = 0.05, which will not be elaborated here.

[0056] Example 6: Dysprosium Oxide and Ytterbium Oxide Co-Doped Indium Zinc Tantalum Oxide Semiconductor Material

[0057] A group of metal oxide semiconductor materials, and this group of metal oxide semiconductor materials is: doping dysprosium oxide as a charge conversion center and ytterbium oxide as a carrier control agent in indium zinc tantalum oxide (InZnTaO) to form a semiconductor material of dysprosium oxide and ytterbium oxide co-doped indium zinc tantalum oxide (Dy-Yb:InZnTaO).

[0058] Among them, MO is tantalum zinc oxide, In:Zn:Ta = 3:1:0.1 mol, marked as In(3)Zn(1)Ta(0.1); In x (ZnTa) y Yb n Dy m O z Among them, x = 0.58, y = 0.2127, m = 0.1573, n = 0.05. However, it is not limited to the above ratios. In some other embodiments, x = 0.6, y = 0.22, m = 0.13, n = 0.05, or x = 0.65, y = 0.2383, m = 0.0617, n = 0.05, or x = 0.68, y = 0.2493, m = 0.0207, n = 0.05, which will not be elaborated here.

[0059] Example 7: Praseodymium Oxide and Europium Oxide Co-Doped Indium Tin Zinc Oxide Film

[0060] A group of metal oxide semiconductor thin films, and this group of metal oxide semiconductor thin films is formed by the Praseodymium Oxide, Oxygen Europium Oxide Co-Doped Indium Tin Zinc Oxide semiconductor material of Example 1 by magnetron sputtering.

[0061] Example 8: Praseodymium Oxide and Ytterbium Oxide Co-Doped Indium Zinc Titanium Oxide Film

[0062] A group of metal oxide semiconductor thin films, and this group of metal oxide semiconductor thin films is formed by the Praseodymium Oxide, Oxygen Ytterbium Oxide Co-Doped Indium Zinc Titanium Oxide semiconductor material of Example 2 by magnetron sputtering.

[0063] Example 9: Terbium Oxide and Europium Oxide Co-Doped Indium Gallium Zinc Oxide Film

[0064] A set of metal oxide semiconductor thin films, and this set of metal oxide semiconductor thin films is composed of those in Example 3 Terbium Oxide, Oxygen Europium Oxide Co-Doped Indium Gallium Zinc Oxide The semiconductor material is prepared by magnetron sputtering.

[0065] Example 10: Terbium Oxide and Ytterbium Oxide Co-Doped Indium Gallium Zirconium Oxide Film

[0066] A set of metal oxide semiconductor thin films, and this set of metal oxide semiconductor thin films is composed of those in Example 4 Terbium Oxide, Oxygen Ytterbium Oxide Co-Doped Indium Gallium Zirconium Oxide The semiconductor material is prepared by magnetron sputtering.

[0067] Example 11: Cerium Oxide and Europium Oxide Co-Doped Indium Zinc Oxide Film

[0068] A set of metal oxide semiconductor thin films, and this set of metal oxide semiconductor thin films is composed of those in Example 5 Cerium Oxide, Oxygen Europium Oxide Co-Doped Indium Zinc Oxide The semiconductor material is prepared by a solution method.

[0069] Example 12: Dysprosium Oxide and Ytterbium Oxide Co-Doped Indium Zinc Tantalum Oxide Film

[0070] A set of metal oxide semiconductor thin films, and this set of metal oxide semiconductor thin films is composed of those in Example 6 Dysprosium Oxide, Oxygen Ytterbium Oxide Co-Doped Indium Zinc Tantalum Oxide The semiconductor material is prepared by magnetron sputtering.

[0071] Example 13: Thin Film Transistor

[0072] A set of thin film transistors, adopting a back-channel etching type structure, and its structural schematic diagram is as Figure 1 shown, and it is provided with: a substrate 01, a gate 05 located above the substrate 01, an insulating layer 04 located above the substrate 01 and the gate 05, a channel layer 03 covering the upper surface of the insulating layer 04 and corresponding to the gate 05, a source electrode 07-1 and a drain electrode 07-2 that are spaced apart from each other and electrically connected to both ends of the channel layer 03, and a spacer layer 06.

[0073] Among them, the substrate 01 is a hard alkali-free glass substrate, and a buffer layer 02 of silicon oxide is covered thereon.

[0074] The material of the gate 05 is a metal molybdenum / copper (Mo / Cu) laminated structure prepared by magnetron sputtering, and the thickness is 20 / 400 nm.

[0075] The insulating layer 04 is a laminated layer of silicon nitride (Si3N4) and silicon oxide (SiO2) prepared by chemical vapor deposition, and the thickness is 250 / 50 nm, wherein the silicon nitride is in contact with the gate 05 in the lower layer, and the silicon oxide is in contact with the channel layer 03 in the upper layer.

[0076] To test the effect of different praseodymium oxide contents on the device performance, the material of the channel layer 03 is the praseodymium oxide and europium oxide co-doped indium tin zinc oxide semiconductor material of Example 1. Using indium tin zinc oxide (InSnZnO), europium-doped indium tin zinc oxide (Eu:InSnZnO), and praseodymium oxide and europium oxide co-doped indium tin zinc oxide (Pr-Eu:InSnZnO) three ceramic targets, the thin films with different composition ratios are prepared by using a single target or co-sputtering of two targets and adjusting the sputtering power of the two targets.

[0077] The materials of the source electrode 07-1 and the drain electrode 07-2 are a metal molybdenum / copper (Mo / Cu) laminated structure with a thickness of 20 / 400 nm. It is patterned by using a commercial hydrogen peroxide-based etching solution, which has less damage to the channel layer 03 and no obvious etching residue.

[0078] The material of the spacer layer 06 is silicon dioxide (SiO2) prepared by chemical vapor deposition, with a thickness of 300 nm and a deposition temperature of 250 °C.

[0079] The thin-film transistor of this embodiment can be a closed structure including only the substrate 01, the gate electrode 05, the insulating layer 04, the channel layer 03, the source electrode 07-1, the drain electrode 07-2, and the spacer layer 06. It can also further include a planarization layer, a reflective electrode, a pixel definition layer, etc., and can also be integrated with other devices.

[0080] Among them, the patterning process of the thin film is carried out by using a photolithography process and combined with wet or dry etching methods.

[0081] The specific parameters in this embodiment and the performance of the prepared thin-film transistor device are shown in Table 1. Among them, the characterization method of the photocurrent characteristics is to irradiate the channel layer 03 of the thin-film transistor device with a commercial white LED light source (light intensity set to 10000 nits), and evaluate the change of the device threshold voltage and sub-threshold swing by evaluating the transfer characteristics of the device under illuminated and non-illuminated conditions to evaluate its strength; a large change in the threshold voltage indicates strong photocurrent characteristics, and vice versa.

[0082] Table 1

[0083]

[0084] It can be seen from Table 1 that the incorporation of praseodymium oxide and europium oxide has a very obvious effect on the device performance. First, as shown in Experiment 1 of Table 1, the device prepared from indium tin zinc oxide without doping praseodymium oxide (m = 0) and europium oxide (n = 0) did not show the "switching" characteristic (conducting state) of the thin-film transistor, indicating that the carrier concentration in the thin film is too high. As shown in Experiment 2 of Table 1, after incorporating a certain amount (corresponding to m = 0, n = 0.05) of europium oxide, the device showed the "switching" characteristic. For details, seeFigure 4 As shown in Fig. (a), it shows that the incorporation of europium oxide can effectively inhibit the carrier concentration in the thin film. The corresponding thin film Hall data are shown in Table 1. Further, as shown in Tests 2 - 8 in Table 1, by adjusting the sputtering power of the target in co-sputtering, a series of devices with different praseodymium contents can be prepared. It should be noted that the device without praseodymium oxide doping (corresponding to m = 0, n = 0.05) has a relatively high mobility, a small subthreshold swing, and a relatively negative threshold voltage. However, its photocurrent characteristic is extremely strong, that is, the device characteristics change very significantly under light illumination conditions (the threshold voltage drifts negatively, and the subthreshold swing degenerates severely). However, after incorporating a certain amount of praseodymium oxide, the photocurrent characteristic of the device is significantly inhibited. Of course, as the content of praseodymium oxide increases, the characteristics such as the mobility of the device further degenerate, and the photocurrent characteristic is further improved. When an excessive amount of praseodymium oxide is incorporated (such as m = 0.15, n = 0.05), the mobility of the device significantly degenerates. Although the photocurrent characteristic of the device is extremely weak, this greatly limits its application fields. Therefore, in practical applications, it is necessary to balance the relationship between the two and select an appropriate incorporation amount.

[0085] The devices prepared in this embodiment are subjected to corresponding photocurrent characteristic tests, as Figure 4 shown in Fig. (b) and Fig. 4(c). The corresponding m values are 0 and 0.05 respectively. When light irradiates on the device, for the device without praseodymium oxide doping (corresponding to m = 0, n = 0.05), the threshold voltage significantly shifts negatively, and the subthreshold swing severely degenerates; while after incorporating a certain amount of praseodymium oxide (corresponding to m = 0.05, n = 0.05), the threshold voltage of the device hardly changes; it shows excellent light stability, that is, the weak photocurrent characteristic corresponding to Table 1.

[0086] The test results of this embodiment show that in the indium tin zinc oxide matrix material of the present invention, incorporating a certain amount of praseodymium oxide and europium oxide can effectively control the carrier concentration of the material and improve the light stability.

[0087] Example 14: Thin Film Transistor

[0088] A group of thin film transistors adopt a back-channel etching type structure, and its structural schematic diagram is as Figure 1 shown, provided with: a substrate 01, a gate electrode 05 located above the substrate 01, an insulating layer 04 located above the substrate 01 and the gate electrode 05, a channel layer 03 covering the upper surface of the insulating layer 04 and corresponding to the gate electrode 05, a source electrode 07 - 1 and a drain electrode 07 - 2 that are spaced apart from each other and electrically connected to both ends of the channel layer 03, and a spacer layer 06.

[0089] Among them, the substrate 01 is a hard alkali-free glass substrate, on which a buffer layer 02 of silicon oxide is covered.

[0090] The material of the gate 05 is a metal molybdenum / copper (Mo / Cu) laminated structure prepared by magnetron sputtering, with a thickness of 20 / 400 nm.

[0091] The insulating layer 04 is a laminate of silicon nitride (Si3N4) and silicon dioxide (SiO2) prepared by chemical vapor deposition, with a thickness of 250 / 50 nm. Among them, silicon nitride is in contact with the gate 05 at the lower layer, and silicon dioxide is in contact with the channel layer 03 at the upper layer.

[0092] To test the influence of different ytterbium oxide contents on the device performance, the material of the channel layer 03 is the praseodymium and ytterbium co-doped indium zinc titanium oxide semiconductor material of Example 2. Using three ceramic targets of indium zinc titanium oxide (InZnTiO), praseodymium-doped indium zinc titanium oxide (Pr:InZnTiO), and praseodymium and ytterbium co-doped indium zinc titanium oxide (Pr-Yb:InZnTiO), the thin films with different composition ratios are prepared by using a single target or co-sputtering of two targets and adjusting the sputtering power of the two targets.

[0093] The materials of the source 07-1 and the drain 07-2 are metal molybdenum / copper (Mo / Cu) laminated structures with a thickness of 20 / 400 nm. They are patterned using a commercial hydrogen peroxide-based etching solution, which has less damage to the channel layer 03 and no obvious etching residues.

[0094] The material of the spacer layer 06 is silicon dioxide (SiO2) prepared by chemical vapor deposition, with a thickness of 300 nm and a deposition temperature of 250 °C.

[0095] The thin-film transistor of this embodiment can be a closed structure including only the substrate 01, the gate 05, the insulating layer 04, the channel layer 03, the source 07-1, the drain 07-2, and the spacer layer 06. It can also further include a planarization layer, a reflective electrode, a pixel definition layer, etc., or can be integrated with other devices.

[0096] Among them, the patterning process of the thin film is carried out by photolithography technology and combined with wet or dry etching methods.

[0097] The specific parameters in this embodiment and the performance of the prepared thin-film transistor device are shown in Table 2. Among them, the characterization method of the photocurrent characteristics is to irradiate the channel layer 03 of the thin-film transistor device with a commercial white LED light source (light intensity set to 10000 nits), and evaluate the change of the device threshold voltage and subthreshold swing by evaluating the transfer characteristics of the device under illuminated and non-illuminated conditions to evaluate its strength. A large change in the threshold voltage indicates strong photocurrent characteristics, and vice versa.

[0098] Table 2

[0099]

[0100] As can be seen from Table 2, the incorporation of praseodymium oxide and ytterbium oxide has a very obvious effect on the device performance. First, as shown in Experiment 1 of Table 2, the device prepared from indium zinc titanium oxide without doping praseodymium oxide (m = 0) and ytterbium oxide (n = 0) did not exhibit the "switching" characteristic (on state) of the thin film transistor, indicating that the carrier concentration in the thin film was too high. As shown in Experiment 2 of Table 2, after incorporating a certain amount (corresponding to m = 0.05, n = 0) of praseodymium oxide, the device still did not exhibit the "switching" characteristic; further, when a certain amount of ytterbium oxide was continuously incorporated (corresponding to m = 0.05, n = 0.0001), the device exhibited the "switching" characteristic; indicating that the inhibitory effect of praseodymium oxide on the carrier concentration in the thin film was not as obvious as that of ytterbium oxide, and the corresponding thin film Hall data are shown in Table 2. To further study the influence of ytterbium oxide, as shown in Experiments 2 to 8 of Table 2, by adjusting the sputtering power of the target in co-sputtering, a series of devices with different ytterbium contents can be prepared. Specifically, the device doped with a small amount of ytterbium oxide (corresponding to m = 0.05, n = 0.0001) has a relatively high mobility and a relatively negative threshold voltage. As the content of ytterbium oxide increases, the threshold voltage of the device shifts positively and the mobility decreases; indicating that ytterbium oxide can effectively regulate the threshold voltage of the device, that is, effectively regulate the carrier concentration in the thin film, which can be further verified from the Hall data in Table 2. Of course, after excessive incorporation of ytterbium oxide (such as m = 0.05, n = 0.15), the mobility of the device is significantly degraded, which greatly limits its application fields. Therefore, in practical applications, it is necessary to balance the relationship between the two and select an appropriate incorporation amount.

[0101] Perform the corresponding photocurrent characteristic test on the device prepared in this embodiment, as Figure 5 (b) and 5(c) show that the corresponding m value is 0.05 and the n values are 0.001 and 0.05 respectively. When light irradiates on the device, for the device doped with a small amount of ytterbium oxide (corresponding to m = 0.05, n = 0.001), the threshold voltage does not shift significantly and the subthreshold swing degrades slightly; in addition, after incorporating a certain amount of ytterbium oxide (corresponding to m = 0.05, n = 0.05), the threshold voltage of the device also hardly changes, showing excellent light stability, that is, corresponding to the weak photocurrent characteristic in Table 2. It should be noted that the photocurrent characteristics of the devices with different ytterbium contents (m = 0.05, n = 0 to 0.15) are all weak, indicating that the incorporation of praseodymium oxide can effectively improve the light stability of the device.

[0102] The test results of this embodiment show that in the indium zinc titanium oxide matrix material of the present invention, incorporating a certain amount of praseodymium oxide and ytterbium oxide can effectively control the carrier concentration of the material and improve the light stability.

[0103] Example 15: Thin Film Transistor

[0104] A group of thin-film transistors, adopting a top-gate self-aligned structure, the schematic structural diagram thereof is as Figure 2 shown, and are provided with: a substrate 01, a buffer layer 02, a channel layer 03, an insulating layer 04 located above the channel layer 03, a gate 05, a spacer layer 06 covering the upper surfaces of the channel layer 03 and the gate, a source 07-1 and a drain 07-2 which are located above the spacer layer 06 and are electrically connected to both ends of the channel layer 03.

[0105] Among them, the substrate 01 is a hard glass substrate.

[0106] The buffer layer 02 is silicon oxide prepared by plasma-enhanced chemical vapor deposition.

[0107] The material of the channel layer 03 is terbium oxide and europium oxide co-doped indium gallium zinc oxide semiconductor material of Example 3, and the thickness is 30 nm.

[0108] The insulating layer 04 is silicon oxide, and the thickness is 300 nm; the gate 05 is a titanium / copper (Ti / Cu) laminated structure prepared by magnetron sputtering, and the thickness is 20 / 400 nm.

[0109] The spacer layer 06 is silicon oxide, and the thickness is 300 nm.

[0110] The materials of the source 07-1 and the drain 07-2 are titanium / copper (Ti / Cu) laminated structures prepared by magnetron sputtering, and the thickness is 20 / 400 nm.

[0111] To test the influence of different europium contents on the device performance, the material of the channel layer 03 is terbium oxide and europium oxide co-doped indium gallium zinc oxide semiconductor material of Example 3, using three ceramic targets of indium gallium zinc oxide (InGaZnO), terbium-doped indium gallium zinc oxide (Tb:InGaZnO), and terbium oxide and europium oxide co-doped indium gallium zinc oxide (Tb-Eu:InGaZnO), and adopting a single target or co-sputtering of two targets, and realizing the preparation of thin films with different composition ratios by adjusting the sputtering power of the two targets.

[0112] The thin-film transistor of this embodiment can be a closed structure only including the substrate 01, the channel layer 03, the insulating layer 04, the gate 05, the spacer layer 06, the source 07-1 and the drain 07-2, or can further include a passivation layer, a pixel definition layer, etc., and can also be integrated with other devices, etc.

[0113] Among them, the patterning of the thin film is carried out by photolithography and combined with wet or dry etching methods.

[0114] The specific parameters and the performance of the fabricated thin-film transistor devices in this embodiment are shown in Table 3. Among them, the characterization method of the photocurrent characteristics is to irradiate the channel layer of the thin-film transistor device with a commercial white LED light source, and by characterizing the transfer characteristics of the device under different light intensity conditions, the change of the threshold voltage of the device is extracted to evaluate its strength; a large change amplitude of the threshold voltage indicates strong photocurrent characteristics, and vice versa.

[0115] Table 3

[0116]

[0117] As can be seen from Table 3, the incorporation of terbium oxide and europium oxide has a very obvious impact on the device performance. First, as shown in Experiment 1 of Table 3, the device fabricated with indium gallium zinc oxide without doping terbium oxide (m = 0) and europium oxide (n = 0) did not exhibit the "switching" characteristic (conducting state) of the thin-film transistor, indicating that the carrier concentration in the thin film is too high. As shown in Experiment 2 of Table 3, after incorporating a certain amount (corresponding to m = 0.05, n = 0) of terbium oxide, the device still did not exhibit the "switching" characteristic; further, when a certain amount of europium oxide was continuously incorporated (corresponding to m = 0.05, n = 0.0001), the device exhibited the "switching" characteristic; indicating that the effect of terbium oxide on suppressing the carrier concentration in the thin film is not as obvious as that of europium oxide, and the corresponding thin-film Hall data are shown in Table 3. To further study the influence of europium oxide, as shown in Experiments 2-8 of Table 3, a series of devices with different europium contents can be fabricated by adjusting the sputtering power of the target in co-sputtering. Specifically, the device doped with a small amount of europium oxide (corresponding to m = 0.05, n = 0.0001) has a relatively high mobility and a more negative threshold voltage. As the europium oxide content increases, the threshold voltage of the device shifts positively and the mobility decreases; indicating that europium oxide can effectively regulate the threshold voltage of the device, that is, effectively regulate the carrier concentration in the thin film, which can be further verified from the Hall data in Table 3. Of course, after incorporating an excessive amount of europium oxide (such as m = 0.05, n = 0.15), the mobility of the device is significantly degraded, which greatly limits its application fields. Therefore, in practical applications, it is necessary to balance the relationship between the two and select an appropriate incorporation amount. The fabricated devices in this embodiment are subjected to corresponding photocurrent characteristic tests, such as Figure 6As shown in Figs. 6(b) and 6(c), the corresponding m value is 0.05, and the n values are 0.001 and 0.05 respectively. When light irradiates the device, for the device doped with a small amount of europium oxide (corresponding to m = 0.05, n = 0.001), the threshold voltage has no obvious shift, and the subthreshold swing slightly degrades; in addition, after doping a certain amount of europium oxide (corresponding to m = 0.05, n = 0.05), the threshold voltage of the device hardly changes, showing excellent light stability, that is, corresponding to the weak photocurrent characteristics in Table 3. It should be noted that the photocurrent characteristics of the devices with different europium contents (m = 0.05, n = 0 - 0.15) are all weak, indicating that the doping of terbium oxide can effectively improve the light stability of the device.

[0118] The test results of this embodiment show that in the indium gallium zinc oxide matrix material of the present invention, doping a certain amount of terbium oxide and europium oxide can effectively control the carrier concentration of the material and improve the light stability.

[0119] Example 16: Thin Film Transistor

[0120] A group of thin film transistors adopts a top-gate self-aligned structure, and its structural schematic diagram is as Figure 2 shown, and is provided with: a substrate 01, a buffer layer 02, a channel layer 03, an insulating layer 04 located above the channel layer 03, a gate electrode 05, a spacer layer 06 covering the upper surfaces of the channel layer 03 and the gate electrode, and a source electrode 07-1 and a drain electrode 07-2 that are electrically connected to both ends of the channel layer 03 above the spacer layer 06.

[0121] Among them, the substrate 01 is a hard glass substrate.

[0122] The buffer layer 02 is silicon oxide prepared by plasma enhanced chemical vapor deposition.

[0123] The material of the channel layer 03 is the terbium oxide and ytterbium oxide co-doped indium gallium zirconium oxide semiconductor material of Example 4, and the thickness is 30 nm.

[0124] The insulating layer 04 is silicon oxide with a thickness of 300 nm; the gate electrode 05 is a titanium / copper (Ti / Cu) laminated structure prepared by magnetron sputtering, and the thickness is 20 / 400 nm.

[0125] The spacer layer 06 is silicon oxide with a thickness of 300 nm.

[0126] The materials of the source electrode 07-1 and the drain electrode 07-2 are titanium / copper (Ti / Cu) laminated structures prepared by magnetron sputtering, and the thickness is 20 / 400 nm.

[0127] To test the influence of different terbium contents on the device performance, the material of the channel layer 03 is the terbium oxide and ytterbium oxide co-doped indium gallium zirconium oxide semiconductor material of Example 4. Using indium gallium zirconium oxide (InGaZrO), terbium-doped indium gallium zirconium oxide (Tb:InGaZrO), and terbium oxide and ytterbium oxide co-doped indium gallium zirconium oxide (Tb-Yb:InGaZrO) three ceramic targets, the thin films with different composition ratios are prepared by using a single target or co-sputtering of two targets and adjusting the sputtering power of the two targets.

[0128] The thin film transistor of this embodiment can be a closed structure including only a substrate 01, a channel layer 03, an insulating layer 04, a gate 05, a spacer layer 06, a source 07-1 and a drain 07-2, or can further include a passivation layer, a pixel definition layer, etc., and can also be integrated with other devices, etc.

[0129] Among them, the patterning of the thin film is carried out by photolithography and combined with wet or dry etching methods.

[0130] The specific parameters in this embodiment and the performance of the prepared thin film transistor device are shown in Table 4. Among them, the characterization method of the photocurrent characteristics is to irradiate the channel layer 03 of the thin film transistor device with a commercial white LED light source, and evaluate its strength by characterizing the transfer characteristics of the device under different light intensity conditions and extracting the change of the device threshold voltage; a large change amplitude of the threshold voltage indicates strong photocurrent characteristics, and vice versa.

[0131] Table 4

[0132]

[0133] It can be seen from Table 4 that the incorporation of terbium oxide and ytterbium oxide has a very obvious influence on the device performance. First, as shown in Experiment 1 of Table 4, the device prepared from indium gallium zirconium oxide without doping terbium oxide (m = 0) and ytterbium oxide (n = 0) did not show the "switching" characteristic (conducting state) of the thin film transistor, indicating that the carrier concentration in the thin film is too high. As shown in Experiment 2 of Table 4, after incorporating a certain amount (corresponding to m = 0, n = 0.05) of ytterbium oxide, the device showed the "switching" characteristic. For details, see Figure 7As shown in (a), it indicates that the incorporation of ytterbium oxide can effectively inhibit the carrier concentration in the thin film, and the corresponding thin film Hall data are shown in Table 4. Further, as shown in Tests 2 - 8 of Table 4, by adjusting the sputtering power of the target in co-sputtering, a series of devices with different terbium contents can be prepared. It should be noted that the device without terbium oxide doping (corresponding to m = 0, n = 0.05) has a relatively high mobility, a small subthreshold swing, and a relatively negative threshold voltage. However, its photocurrent characteristic is extremely strong, that is, the device characteristics change very significantly under light illumination conditions (the threshold voltage drifts negatively, and the subthreshold swing degrades severely). However, after incorporating a certain amount of terbium oxide, the photocurrent characteristic of the device is significantly inhibited. Of course, as the content of terbium oxide increases, the characteristics such as the mobility of the device further degrade, and the photocurrent characteristic is further improved. When an excessive amount of terbium oxide is incorporated (such as m = 0.15, n = 0.05), the mobility of the device significantly degrades. Although the photocurrent characteristic of the device is extremely weak, this greatly limits its application fields. Therefore, in practical applications, it is necessary to balance the relationship between the two and select an appropriate incorporation amount.

[0134] Perform the corresponding photocurrent characteristic test on the device prepared in this embodiment, as Figure 7 shown in (b) and 7(c), the corresponding n value is 0.05, and the m values are 0 and 0.05 respectively. When light irradiates on the device, for the device without terbium oxide doping (corresponding to m = 0, n = 0.05), the threshold voltage significantly shifts negatively, and the subthreshold swing severely degrades; while after incorporating a certain amount of terbium oxide (corresponding to m = 0.05, n = 0.05), the threshold voltage of the device hardly changes; it shows excellent light stability, that is, the weak photocurrent characteristic corresponding to Table 4.

[0135] The test results of this embodiment show that in the indium gallium zirconium oxide matrix material of the present invention, incorporating a certain amount of terbium oxide and ytterbium oxide can effectively control the carrier concentration of the material and improve the light stability.

[0136] Example 17: Thin Film Transistor

[0137] A group of thin film transistors, adopting a self-aligned structure, and its structural schematic diagram is as Figure 2 shown, provided with: a substrate 01, a buffer layer 02, a channel layer 03, an insulating layer 04 located above the channel layer 03, a gate 05, a spacer layer 06 covering the upper surfaces of the channel layer 03 and the gate 05, a source electrode 07 - 1 and a drain electrode 07 - 2 which are electrically connected to both ends of the channel layer 03 above the spacer layer 06.

[0138] Among them, the substrate 01 is a hard glass substrate.

[0139] The buffer layer 02 is silicon oxide prepared by plasma enhanced chemical vapor deposition.

[0140] The material of the channel layer 03 is the cerium oxide and europium oxide co-doped indium zinc oxide semiconductor material of Example 5, and the thickness is 20 nm.

[0141] The insulating layer 04 is silicon oxide, and the thickness is 300 nm; the gate 05 is a molybdenum / copper / molybdenum (Mo / Cu / Mo) laminated structure prepared by magnetron sputtering, and the thickness is 20 / 400 / 50 nm.

[0142] The spacer layer 06 is a silicon oxide thin film prepared by plasma enhanced chemical vapor deposition, and the thickness is 300 nm.

[0143] The materials of the source electrode 07-1 and the drain electrode 07-2 are molybdenum / copper / molybdenum (Mo / Cu / Mo) laminated structures prepared by magnetron sputtering, and the thickness is 20 / 400 / 50 nm.

[0144] The thin film transistor of this embodiment can be a closed structure only including the substrate 01, the channel layer 03, the insulating layer 04, the gate 05, the spacer layer 06, the source electrode 07-1 and the drain electrode 07-2, and can also further include a passivation layer, a pixel definition layer, etc., and can also be integrated with other devices, etc.

[0145] Among them, the patterning of the thin film is carried out by photolithography and combined with wet or dry etching methods.

[0146] The specific parameters and the performance of the prepared thin film transistor device in this embodiment are shown in Table 5. Among them, the characterization method of the photocurrent characteristics is to irradiate the channel layer 03 of the thin film transistor device with a commercial white LED light source, and by characterizing the transfer characteristics of the device under different light intensity conditions, the change of the threshold voltage of the device is extracted to evaluate its strength; the larger the change amplitude of the threshold voltage, the stronger the photocurrent characteristics of it, and vice versa.

[0147] Table 5

[0148]

[0149] It can be seen from this Table 5 that the incorporation of cerium oxide and europium oxide has a very obvious influence on the device performance. First, as shown in Test 1 of Table 5, the device prepared from indium zinc oxide without doping cerium oxide (m = 0) and europium oxide (n = 0) does not show the "switching" characteristic (conducting state) of the thin film transistor, indicating that the carrier concentration in the thin film is too high. As shown in Test 2 of Table 5, after incorporating a certain amount (corresponding to m = 0, n = 0.05) of europium oxide, the device shows the "switching" characteristic. For details, see Figure 8As shown in Fig. (a), it shows that the incorporation of europium oxide can effectively inhibit the carrier concentration in the thin film. The corresponding Hall data of the thin film are shown in Table 5. Further, as shown in Tests 2-8 of Table 5, a series of devices with different cerium contents can be prepared by adjusting the components in the prepared solution. It should be noted that the device without cerium oxide doping (corresponding to m = 0, n = 0.05) has a relatively high mobility, a small subthreshold swing, and a relatively negative threshold voltage. However, its photocurrent characteristics are extremely strong, that is, the device characteristics change very significantly under light illumination conditions (the threshold voltage drifts negatively, and the subthreshold swing degenerates severely). However, after incorporating a certain amount of cerium oxide, the photocurrent characteristics of the device are significantly inhibited. Of course, as the content of cerium oxide increases, the characteristics such as the mobility of the device further degenerate, and the photocurrent characteristics are further improved. When an excessive amount of cerium oxide is incorporated (such as m = 0.15, n = 0.05), the mobility of the device significantly degenerates. Although the photocurrent characteristics of the device are extremely weak, this greatly limits its application fields. Therefore, in practical applications, it is necessary to balance the relationship between the two and select an appropriate doping amount.

[0150] Perform the corresponding photocurrent characteristic test on the device prepared in this embodiment, as Figure 8 As shown in Fig. (b) and Fig. 8(c), the corresponding n value is 0.05, and the m values are 0 and 0.05 respectively. When light irradiates on the device, the threshold voltage of the device without cerium oxide doping (corresponding to m = 0, n = 0.05) significantly shifts negatively, and the subthreshold swing severely degenerates; while after incorporating a certain amount of cerium oxide (corresponding to m = 0.05, n = 0.05), the threshold voltage of the device hardly changes; it shows excellent light stability, that is, the weak photocurrent characteristics corresponding to Table 5.

[0151] The test results of this embodiment show that in the indium zinc oxide matrix material of the present invention, incorporating a certain amount of cerium oxide and europium oxide can effectively control the carrier concentration of the material and improve the light stability.

[0152] Example 18: Thin Film Transistor

[0153] A group of thin film transistors adopt an etching barrier type structure, and its structural schematic diagram is as Figure 3 shown, and are provided with: a substrate 01, a gate electrode 05 located on the substrate 01, an insulating layer 04 located on the substrate 01 and the gate electrode 05, a channel layer 03 covering the upper surface of the insulating layer 04 and corresponding to the gate electrode 05, an etching barrier layer 08, a source electrode 07-1 and a drain electrode 07-2 that are spaced apart from each other and electrically connected to both ends of the channel layer 03, and a spacer layer 06.

[0154] Among them, the substrate 01 is a glass substrate, and a buffer layer 02 of silicon oxide is covered thereon.

[0155] The material of the gate 05 is a molybdenum-aluminum-molybdenum (Mo / Al / Mo) metal laminate structure prepared by magnetron sputtering, with a thickness of 50 / 300 / 50 nm.

[0156] The insulating layer 04 is a laminate of silicon nitride (Si3N4) and silicon dioxide (SiO2) prepared by chemical vapor deposition, with a thickness of 250 / 50 nm; among them, silicon nitride is in contact with the gate 05 at the lower layer, and silicon dioxide is in contact with the channel layer 03 at the upper layer.

[0157] To test the influence of different dysprosium oxide contents on the device performance, the material of the channel layer 03 is the dysprosium oxide and ytterbium oxide co-doped indium zinc tantalum oxide semiconductor material of Example 6, which is prepared by using three ceramic targets of indium zinc tantalum oxide (InZnTaO), ytterbium-doped indium zinc tantalum oxide (Yb:InZnTaO), and dysprosium oxide and ytterbium co-doped indium zinc tantalum oxide (Dy-Yb:InZnTaO), and adopting a single target or a co-sputtering method of two targets, and adjusting the sputtering power of the two targets to realize the preparation of thin films with different composition ratios.

[0158] The materials of the etch stop layer 08 and the spacer layer 06 are silicon dioxide (SiO2) thin films prepared by chemical vapor deposition, with a thickness of 300 nm each, and the deposition temperature is 300 °C.

[0159] The materials of the source 07-1 and the drain 07-2 are molybdenum-aluminum-molybdenum (Mo / Al / Mo) laminate structures, with a thickness of 50 / 300 / 50 nm.

[0160] In addition, the thin film transistor of this embodiment can be a closed structure including only the substrate 01, the gate 05, the insulating layer 04, the channel layer 03, the etch stop layer 08, the source 07-1 and the drain 07-2, and the passivation layer, or can further include a planarization layer, a reflective electrode, a pixel definition layer, etc., and can also be integrated with other devices, etc.

[0161] Among them, the patterning process of the thin film is carried out by photolithography technology and combined with wet or dry etching methods.

[0162] The specific parameters in this embodiment and the performance of the prepared thin film transistor device are shown in Table 6. Among them, the characterization method of the photocurrent characteristic is to irradiate the channel layer 03 of the thin film transistor device with a commercial white LED light source, and evaluate the transfer characteristics of the device under illuminated and non-illuminated conditions, and extract the change of the device threshold voltage to evaluate its strength; a large change amplitude of the threshold voltage indicates a strong photocurrent characteristic, and vice versa.

[0163] Table 6

[0164]

[0165] As can be seen from Table 6, the incorporation of dysprosium oxide and ytterbium oxide has a very obvious effect on the device performance. First, as shown in Experiment 1 of Table 6, the device prepared from indium zinc tantalum oxide without doping dysprosium oxide (m = 0) and ytterbium oxide (n = 0) did not exhibit the "switching" characteristic (conducting state) of the thin-film transistor, indicating that the carrier concentration in the thin film was too high. As shown in Experiment 2 of Table 6, after incorporating a certain amount (corresponding to m = 0, n = 0.05) of ytterbium oxide, the device exhibited the "switching" characteristic. See Figure 9 as shown in (a), indicating that the incorporation of ytterbium oxide can effectively inhibit the carrier concentration in the thin film. The corresponding thin-film Hall data are shown in Table 6. Further, as shown in Experiments 2-8 of Table 6, by adjusting the sputtering power of the corresponding target, a series of devices with different dysprosium contents can be prepared. It should be noted that the device without doping dysprosium oxide (corresponding to m = 0, n = 0.05) has a relatively high mobility, a small subthreshold swing, and a relatively negative threshold voltage, but its photocurrent characteristic is extremely strong, that is, the device characteristics change very significantly under light illumination (the threshold voltage drifts negatively, and the subthreshold swing degenerates severely). However, after incorporating a certain amount of dysprosium oxide, the photocurrent characteristic of the device is significantly inhibited. Of course, as the content of dysprosium oxide increases, the characteristics such as the mobility of the device also further degenerate, and the photocurrent characteristic is further improved. When an excessive amount of dysprosium oxide is incorporated (such as m = 0.15, n = 0.05), the mobility of the device significantly degenerates. Although the photocurrent characteristic of the device is extremely weak, this greatly limits its application fields. Therefore, in practical applications, it is necessary to balance the relationship between the two and select an appropriate incorporation amount.

[0166] The device prepared in this embodiment was subjected to the corresponding photocurrent characteristic test. As Figure 9 shown in (b) and 9(c), the corresponding n value is 0.05, and the m values are 0 and 0.05 respectively. When light is irradiated on the device, for the device without doping dysprosium oxide (corresponding to m = 0, n = 0.05), the threshold voltage significantly shifts negatively, and the subthreshold swing degenerates severely; while after incorporating a certain amount of dysprosium oxide (corresponding to m = 0.05, n = 0.05), the threshold voltage of the device hardly changes; it exhibits excellent light stability, that is, the weak photocurrent characteristic corresponding to Table 6.

[0167] The test results of this embodiment show that in the indium zinc tantalum oxide matrix material of the present invention, incorporating a certain amount of dysprosium oxide and ytterbium oxide can effectively control the carrier concentration of the material and improve the light stability.

[0168] Example 19: Display Panel

[0169] A display panel includes the thin-film transistor in the above-mentioned Embodiments 13-18, and the thin-film transistor is used to drive the display unit in the display panel.

[0170] Example 20: Detector

[0171] A detector includes the thin-film transistors in the above Embodiments 13-18, and the thin-film transistors are used to drive the detection units of the detector.

[0172] Next, further descriptions will be made on the functional layers of the thin-film transistors implemented in the present invention.

[0173] The substrate in the present invention is not particularly limited, and the substrates well-known in the art can be used, such as substrate 01. For example: hard alkali glass, alkali-free glass, quartz glass, silicon substrate, etc.; it can also be bendable polyimide (PI), polyethylene naphthalate (PEN), polyethylene terephthalate (PET), polyethylene (PE), polypropylene (PP), polystyrene (PS), polyethersulfone (PES), or metal foil, etc.

[0174] The gate 05 material in the present invention is not particularly limited, and it can be arbitrarily selected from the materials well-known in the art. For example: transparent conductive oxides (ITO, AZO, GZO, IZO, ITZO, FTO, etc.), metals (Mo, Al, Cu, Ag, Ti, Au, Ta, Cr, Ni, etc.) and their alloys, as well as composite conductive films formed by metals and oxides (ITO / Ag / ITO, IZO / Ag / IZO, etc.), metals and metal stacks (Mo / Al / Mo, Ti / Al / Ti, etc.).

[0175] The preparation method of the gate 05 thin film can be sputtering method, electroplating, thermal evaporation, and other deposition methods. The sputtering deposition method is preferred because the film prepared by this method has good adhesion to the substrate 01, excellent uniformity, and can be prepared in large areas.

[0176] Here, which structure of the gate electrode is specifically used needs to be determined according to the technical parameters to be achieved. For example, in transparent displays, a transparent electrode is required, and it can be a single-layer ITO as the gate electrode, or ITO / Ag / ITO as the gate electrode. In addition, in applications in special fields where high-temperature processes are required, the gate electrode can be a metal alloy film that can resist high temperatures.

[0177] The insulating layer 04 material in the present invention is not particularly limited, and it can be arbitrarily selected from the materials well-known in the art. For example: silicon oxide, silicon nitride, aluminum oxide, tantalum oxide, hafnium oxide, yttrium oxide, and polymer organic film layers, etc.

[0178] It should be noted that the components of these insulating films may not be consistent with the theoretical stoichiometric ratio. In addition, the insulating layer 04 can be formed by stacking multiple insulating films, which can form better insulating properties on the one hand and improve the interface properties between the channel layer 03 and the insulating layer 04 on the other hand. Moreover, the insulating layer 04 can be prepared in various ways, such as physical vapor deposition, chemical vapor deposition, atomic layer deposition, laser deposition, anodic oxidation, or solution method.

[0179] The etching solution used for wet etching includes: a mixed solution of phosphoric acid, nitric acid, and glacial acetic acid or a mixed solution based on hydrogen peroxide. The etching rate of the metal oxide semiconductor material in the hydrogen peroxide-based etching solution is less than 1 nm / min. For dry etching, by way of example, a plasma etching process can be selected, and the etching gas includes chlorine-based or fluorine-based gases.

[0180] During the vacuum magnetron sputtering process of the metal oxide semiconductor material, single-target sputtering or multi-target co-sputtering can be selected, and single-target sputtering is preferably used.

[0181] Because single-target sputtering can provide a film with better repeatability and stability, and the microstructure of the film is easier to control; unlike in the co-sputtered film, the sputtered particles will be interfered by more factors during the recombination process.

[0182] During the vacuum sputtering deposition process, the power supply can be selected from radio frequency (RF) sputtering, direct current (DC) sputtering, or alternating current (AC) sputtering, and AC sputtering commonly used in industry is preferably used.

[0183] During the sputtering deposition process, the sputtering gas pressure can be selected from 0.1 Pa to 10 Pa, and preferably 0.3 Pa to 0.7 Pa.

[0184] When the sputtering gas pressure is too low, stable glow sputtering cannot be maintained; when the sputtering gas pressure is too high, the scattering of sputtered particles during the deposition process onto the substrate 01 increases significantly, the energy loss increases, the kinetic energy decreases after reaching the substrate 01, and the film defects increase, thus seriously affecting the performance of the device.

[0185] During the sputtering deposition process, the oxygen partial pressure can be selected from 0 to 1 Pa, preferably 0.001 to 0.5 Pa, and more preferably 0.01 to 0.1 Pa.

[0186] Generally speaking, during the process of sputtering to prepare an oxide semiconductor, the oxygen partial pressure has a direct impact on the carrier concentration of the film and will introduce some defects related to oxygen vacancies. Too low oxygen content may cause serious oxygen mismatch in the film and an increase in the carrier concentration; while too many oxygen vacancies will cause more weakly bonded bonds, reducing the reliability of the device.

[0187] During the sputtering deposition process, the substrate temperature is preferably 200 - 300 °C.

[0188] During the process of depositing the channel layer thin film, a certain substrate temperature can effectively improve the bonding mode of sputtered particles after reaching the substrate 01, reduce the existence probability of weakly bonded bonds, and enhance the stability of the device. Of course, this effect can also be achieved through subsequent annealing processes and other processes.

[0189] The thickness of the channel layer 03 can be selected from 2 to 100 nm, preferably 5 to 50 nm, and more preferably 20 to 40 nm.

[0190] The source-drain electrode material in the present invention is not particularly limited, and it can be arbitrarily selected from the materials well-known in the art on the premise of not affecting the realization of various required structure devices. Such as: transparent conductive oxides (ITO, AZO, GZO, IZO, ITZO, FTO, etc.), metals (Mo, Al, Cu, Ag, Ti, Au, Ta, Cr, Ni, etc.) and their alloys, as well as composite conductive films formed by metals and oxides (ITO / Ag / ITO, IZO / Ag / IZO, etc.), metals and metal stacks (Mo / Al / Mo, Ti / Al / Ti, etc.).

[0191] The preparation method of the source-drain electrode thin film can be sputtering method, thermal evaporation and other deposition methods, and the sputtering deposition method is preferred because the film prepared by this method has good adhesion to the substrate 01, excellent uniformity, and can be prepared in large areas.

[0192] Here, it needs to be particularly noted that in the preparation of the device with a back-channel etching type structure, the source-drain electrode and the channel layer 03 need to have a suitable etching selectivity ratio, otherwise the preparation of the device cannot be achieved. In the embodiments of the present invention, the etching solution for wet etching is an etching solution based on conventional metals in the industry (such as: hydrogen peroxide-based etching solution), mainly because a metal oxide semiconductor material of the present invention can effectively resist the etching of the wet hydrogen peroxide-based etching solution, and it has a high etching selectivity ratio with metals (such as molybdenum, molybdenum alloy, Mo / Al / Mo, etc.). The metal oxide semiconductor layer is basically not affected by the etching solution, and the prepared device has excellent performance and good stability. In addition, the dry etching in the embodiments of the present invention is based on conventional etching gases in the industry (such as chlorine-based gases, fluorine-based gases, etc.), which has little influence on the oxide semiconductor layer of the present invention, and the prepared device has excellent performance and good stability.

[0193] The passivation layer material in the present invention is not particularly limited, and it can be arbitrarily selected from the materials well-known in the art. Such as: silicon oxide, silicon nitride, aluminum oxide, tantalum oxide, hafnium oxide, yttrium oxide, and polymer organic film layers, etc.

[0194] It should be noted that the components of these insulating films may not be consistent with the theoretical stoichiometric ratio. Additionally, the insulating layer 04 can be formed by stacking multiple insulating films, which can form better insulating properties on the one hand and improve the interfacial properties between the channel layer 03 and the passivation layer on the other hand. Moreover, the passivation layer can be prepared in various ways, such as physical vapor deposition, chemical vapor deposition, atomic layer deposition, laser deposition, or solution method.

[0195] Next, the processing techniques in the preparation process of the thin-film transistor according to the present invention will be further described.

[0196] Relatively speaking, due to the participation of high-energy plasma in the sputtering preparation of thin films, the deposition rate of the deposited thin films is generally relatively fast; the thin films do not have enough time to perform relaxation processes during deposition, which will cause a certain proportion of dislocation and stress to remain in the thin films. This requires post-heating annealing treatment to further reach the required relative steady state and improve the performance of the thin films.

[0197] In the implementation of the present invention, the annealing treatment is mostly set after the deposition of the channel layer 03 and after the deposition of the passivation layer. On the one hand, annealing treatment after the deposition of the channel layer 03 can effectively improve the in-situ defects in the channel layer 03 and enhance the ability of the channel layer 03 to resist possible damage in subsequent processes. On the other hand, during the subsequent deposition of the passivation layer, due to the participation of plasma and the modification effect of active groups, this may require an "activation" process to further eliminate interface states and some donor doping effects.

[0198] In addition, in the implementation of the present invention, the processing method can not only be heat treatment, but can also include plasma treatment of interfaces (such as the interface between the insulating layer 04 / semiconductor, the interface between the channel layer 03 / passivation layer, etc.).

[0199] Through the above processing techniques, the performance of the device can be effectively improved and the stability of the device can be enhanced.

[0200] The above embodiments are the preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications made without departing from the spirit and principle of the present invention shall be equivalent replacement methods and are all included in the protection scope of the present invention.

Claims

1. A metal oxide semiconductor, characterized in that, The metal oxide semiconductor is: in a metal oxide MO-In2O3 semiconductor containing indium, oxides of at least two rare earth elements R and oxides of a rare earth element R' are respectively doped to form In x M y R n R' m O z semiconductor material, where x + y + m + n = 1, 0.4 ≤ x < 0.9999, 0 ≤ y < 0.5, 0.0001 ≤ (m + n) ≤ 0.2, m > 0, n > 0, z > 0; In the MO, M is one of Zn, Ga, Sn, Ge, Sb, Al, Mg, Ti, Zr, Hf, Ta, W or a combination of any two or more of these materials; The oxide of the rare earth element R is a carrier concentration controller; The oxide of the rare earth element R is one of ytterbium oxide and europium oxide or a combination of the two materials; The oxide of the rare earth element R' is a light stabilizer; The oxide of the rare earth element R' is one of praseodymium oxide, terbium oxide, cerium oxide, dysprosium oxide or a combination of any two or more of them.

2. The metal oxide semiconductor according to claim 1, characterized in that, The metal oxide semiconductor is formed into a film by any one of physical vapor deposition process, chemical vapor deposition process, atomic layer deposition process, laser deposition process, reactive ion deposition process, solution process.

3. A thin film transistor, the thin film transistor comprising a gate, an active layer, an insulating layer located between the gate and the active layer, a source electrode and a drain electrode electrically connected to both ends of the active layer respectively, and a spacer layer, characterized in that, The active layer is the metal oxide semiconductor described in claim 1 or 2.

4. The thin film transistor according to claim 3, wherein The spacer layer is one of silicon oxide, silicon nitride, silicon oxynitride thin films prepared by plasma enhanced chemical vapor deposition or a stacked structure composed of any two or more of them.

5. The application of the thin film transistor according to claim 3 or 4 in a display panel or a detector.

Images