CN1822331A - Method for preparing titanium silicide nanowires by chemical vapor deposition - Google Patents

Abstract

Present invention discloses a method for preparing titanium silicide nano wire by chemical vapour deposition process. Said method adopts vapour deposition process using SiH4 and TiCl4 as reactant, using N2 as diluents and shielding gas atmosphere. Said method firstly form metal silicide (Ti 5Si3, TiSi2or Ti 5Si3and TiSi2 compound) thin layer, then to form high density silicide (TiSi, Ti 5 Si3 or TiSi2) nano wire. Nano wire diameter is between 10-40 nm, length between 10 micrometer, nano wire pattern can be controlled by changing technological conditions, nano wire chemical constitution can be controlled by changing mol ratio of reactant SiH4 / TiCl4.

Description

Method for preparing titanium silicide nanowires by chemical vapor deposition

technical field

The invention relates to the preparation technology of titanium silicide nanowires. In particular, it relates to the rapid formation of high-density silicide nanowires on glass substrates by chemical vapor deposition.

Background technique

With the development of microelectronics technology, the preparation of nanowires has attracted widespread attention in recent years. Nanowires have broad application prospects as basic modules in nanoelectronics and optoelectronics manufacturing technologies. The application of nanomaterials in semiconductor technology can achieve higher device density, which is unmatched by conventional semiconductor technology. Metal silicides are widely used in modern semiconductor technology for metal oxide semiconductor (MOS) devices in ULSI, metal oxide semiconductor field effect transistors (MOSFET), gates, source/drain and interconnection of dynamic random access memory (DRAM), During the manufacture of ohmic contacts. With the continuous reduction of device size in microelectronics, many one-dimensional metal silicide nanowires have been fabricated. He et al. prepared CoSi ₂ nanowires, Chen et al. prepared ErSi ₂ nanowires, Lee et al. prepared NiSi nanowires, Luo et al. prepared Pt ₆ Si ₅ nanowires, Ragana et al. prepared epitaxial rare metal silicide However, these nanowires are formed by physical vapor deposition methods, mainly sputtering. This method has high requirements on equipment and low output. In order to overcome the shortcomings of the above methods for preparing metal silicide nanowires, we successfully prepared titanium silicide nanowires by chemical vapor deposition, which is a new method for growing metal silicide nanowires, which can be applied to various The preparation of metal silicide nanowires can also be used in the preparation of various inorganic compound nanowires.

Contents of the invention

The object of the present invention is to provide a method for preparing titanium silicide nanowires by chemical vapor deposition.

The technical solution adopted by the present invention to solve its technical problems is that the steps of the method are as follows:

1) The reactants are SiH ₄ and TiCl ₄ , with N ₂ as the dilution gas and protective atmosphere;

2) The constant temperature of TiCl ₄ is 30-60°C; the pipeline through which TiCl ₄ passes is kept warm to 40-70°C;

3) Carrying TiCl ₄ with N ₂ through a gas generator;

4) SiH ₄ , TiCl ₄ and N ₂ are mixed in the gas mixing chamber; the pressure of each gas at the inlet of the gas mixing chamber is equal, and the pressure is kept between 111325-131325Pa;

5) The molar concentration of each substance in the total reaction gas:

a) SiH ₄ : 0.33-5%;

b) TiCl ₄ : 0.33-1.67%;

c) SiH ₄ : TiCl ₄ molar ratio: 1-3;

6) The growth system is a quartz tube reactor, and the pressure of the growth system is 101325-121325Pa;

7) The glass substrate is placed in a quartz tube reactor. The temperature of the glass substrate is 690-750 ° C. The mixed gas of SiH ₄ , TiCl ₄ and N ₂ is transported to the glass substrate for reaction. The reaction time is 30-300 seconds. A titanium silicide film layer is first formed on the substrate, and then high-density silicide nanowires are formed on the metal silicide film;

8) The exhaust gas is discharged after absorption treatment.

The thin film is Ti ₅ Si ₃ , TiSi ₂ or a compound of Ti ₅ Si ₃ and TiSi ₂ . The nanowires are TiSi, Ti ₅ Si ₃ or TiSi ₂ . Said nanowires are single crystal nanowires. The diameter of the nanowire is between 10-40nm, and the length is between 0.2-10μm.

The beneficial effect that the present invention has compared with background technology is:

1. Prepare metal silicide nanowires by CVD method. This method has low equipment requirements, but has large output and high efficiency. Compared with the existing physical vapor deposition method, it has greater advantages;

2. This method does not use templates and catalysts, and quickly generates a large number of single-crystal titanium silicide nanowires;

3. By changing the preparation conditions, nanowires with various shapes can be obtained;

4. Nanowires with various chemical compositions can be obtained by changing the molar ratio of the prepared reactants.

Description of drawings

Fig. 1 nanowire growth schematic diagram of the present invention;

The scanning electron microscope sectional view of the TiSi nanowire sample prepared by Fig. 2 embodiment 1;

The scanning electron micrograph of the TiSi nanowire prepared in Fig. 3 embodiment 2;

Fig. 4 is a high-resolution transmission electron microscope image and an electron diffraction image of the TiSi nanowire prepared in Example 2.

Detailed ways

As shown in FIG. 1 , on an ordinary glass substrate 1 , a thin film 2 is deposited first, and then titanium silicide nanowires 3 are formed on the thin film 2 .

The thin film is Ti ₅ Si ₃ , TiSi ₂ or a compound of Ti ₅ Si ₃ and TiSi ₂ . The nanowires are TiSi, Ti ₅ Si ₃ or TiSi ₂ . Said nanowires are single crystal nanowires. The diameter of the nanowire is between 10-40nm, and the length is between 0.2-10μm.

Below are embodiments of the present invention:

Example 1

The reaction temperature is 690°C, the constant temperature of TiCl ₄ is 60°C, the pipeline through which TiCl ₄ passes is kept warm to 70°C, the molar ratio of reaction gas SiH ₄ : TiCl ₄ is adjusted to 1, SiH ₄ : 1.67%, TiCl ₄ : 1.67%, N ₂ : 96.66%, the pressure of each gas at the inlet of the gas mixing chamber is 111325Pa, the pressure of the growth system is maintained at 101325Pa, and the deposition time is about 120 seconds. Form Ti ₅ Si ₃ film and TiSi single crystal nanowire on the glass substrate. The results are shown in the attached table and Figure 2.

Example 2

The reaction temperature is 690°C, the constant temperature of TiCl ₄ is 40°C, the pipeline through which TiCl ₄ passes is kept warm to 50°C, and the molar ratio of reaction gas SiH ₄ : TiCl ₄ is adjusted to 1, SiH ₄ : 1%, TiCl ₄ : 1%, N ₂ : 98%, the pressure of each gas at the inlet of the gas mixing chamber is 111325Pa, the pressure of the growth system is maintained at 101325Pa, and the deposition time is about 300 seconds. Form Ti ₅ Si ₃ film and TiSi single crystal nanowire on the glass substrate. The results are shown in the attached table and Figures 3-4.

Example 3

The reaction temperature is 690°C, the constant temperature of TiCl ₄ is 30°C, the pipeline passed by TiCl ₄ is kept warm to 40°C, and the molar ratio of SiH ₄ : TiCl ₄ is adjusted to 1, SiH ₄ : 0.33%, TiCl ₄ : 0.33%, N ₂ : 99.34%, the pressure of each gas at the inlet of the gas mixing chamber is 111325Pa, the pressure of the growth system is maintained at 101325Pa, and the deposition time is about 210 seconds. Form Ti ₅ Si ₃ film and TiSi single crystal nanowire on the glass substrate. See the attached table for the results.

Example 4

The reaction temperature is 700°C, the constant temperature of TiCl ₄ is 40°C, the pipeline through which TiCl ₄ passes is kept warm to 50°C, and the molar ratio of reaction gas SiH ₄ : TiCl ₄ is adjusted to 2, SiH ₄ : 3%, TiCl ₄ : 1.5%, N ₂ : 95.5%, the pressure of each gas at the inlet of the gas mixing chamber is 121325Pa, the pressure of the growth system is maintained at 111325Pa, and the deposition time is about 120 seconds. Form Ti ₅ Si ₃ film and Ti ₅ Si ₃ single crystal nanowire on the glass substrate. See the attached table for the results.

Example 5

The reaction temperature is 700°C, the constant temperature of TiCl ₄ is 60°C, the pipeline through which TiCl ₄ passes is kept warm to 70°C, and the molar ratio of reaction gas SiH ₄ : TiCl ₄ is adjusted to 3, SiH ₄ : 5%, TiCl ₄ : 1.67%, N ₂ : 93.33%, the pressure of each gas at the inlet of the gas mixing chamber is 121325Pa, the pressure of the growth system is maintained at 111325Pa, and the deposition time is about 30 seconds. _TiSi2 thin films and _TiSi2 single crystal nanowires were formed on glass substrates. See the attached table for the results.

Example 6

The reaction temperature is 690°C, the constant temperature of TiCl ₄ is at 40°C, the pipeline through which TiCl ₄ passes is kept warm to 50°C, and the molar ratio of reaction gas SiH ₄ : TiCl ₄ is adjusted to 3, SiH ₄ : 1.5%, TiCl ₄ : 0.5%, N ₂ : 98%, the deposition time is about 60 seconds, the pressure of each gas at the inlet of the gas mixing chamber is 131325Pa, and the pressure of the growth system is maintained at 121325Pa. Form a _TiSi2 thin film on a glass substrate. Then, adjust the reaction gas SiH ₄ /TiCl ₄ molar ratio to 1, SiH ₄ : 1%, TiCl ₄ : 1%, N ₂ : 98%, the deposition time is about 90 seconds, and the pressure of each gas at the inlet of the gas mixing chamber is 131325Pa, and the growth system pressure is maintained at 121325Pa. Formation of TiSi single crystal nanowires on _TiSi2 films. See the attached table for the results.

Example 7

The reaction temperature is 750°C, the constant temperature of TiCl ₄ is 40°C, the pipeline through which TiCl ₄ passes is kept warm to 50°C, and the molar ratio of the reaction gas SiH ₄ : TiCl ₄ is adjusted to 1, SiH ₄ : 1%, TiCl ₄ : 1%, N ₂ : 98%, the deposition time is about 40 seconds, the pressure of each gas at the inlet of the gas mixing chamber is 131325Pa, and the pressure of the growth system is maintained at 121325Pa. A Ti ₅ Si ₃ thin film was formed on a glass substrate. Then, adjust the reaction gas SiH ₄ /TiCl ₄ molar ratio to 2, SiH ₄ : 2%, TiCl ₄ : 1%, N ₂ : 97%, the deposition time is about 80 seconds, the pressure of each gas at the inlet of the gas mixing chamber is 131325Pa, and the growth system pressure is maintained at 121325Pa. Formation of TiSi ₂ single crystal nanowires on Ti ₅ Si ₃ film. See the attached table for the results.

Attached Table Characterization of Thin Films example crystal phase in thin film Chemical Composition of Nanowires Atomic ratio Ti:Si in nanowires Nanowire diameter (nm) Nanowire length (μm) Example 1 Ti ₅ Si ₃ TiSi 1:1.1 20 0.5 Example 2 Ti ₅ Si ₃ TiSi 1:1.05 15～25 5～10 Example 3 Ti ₅ Si ₃ TiSi 1:1.07 15～25 0.2 Example 4 Ti ₅ Si ₃ , TiSi ₂ Ti ₅ Si ₃ 1:0.64 15～20 2～3 Example 5 _{TiSi2 TiSi2} 1:2.1 10～25 3～5 Example 6 _TiSi2 TiSi 1:1.1 20～40 0.5～1 Example 7 Ti ₅ Si _{3 TiSi2} 1:2.15 15～25 3～4

The crystal phase in the film was tested by X-ray diffractometer.

The chemical composition of the nanowires was tested by X-ray diffractometer and electron diffraction

The diameter and length of the nanowires were tested by scanning electron microscopy and transmission electron microscopy.

The contained elements and their proportions are tested by X-ray energy dispersive spectrometer.

Claims (5)

1. A method for preparing titanium silicide nanowires by chemical vapor deposition, characterized in that the steps of the method are as follows: 1) The reactants are SiH ₄ and TiCl ₄ , with N ₂ as the dilution gas and protective atmosphere; 2) The constant temperature of TiCl ₄ is 30-60°C; the pipeline through which TiCl ₄ passes is kept warm to 40-70°C; 3) Carrying TiCl ₄ with N ₂ through a gas generator; 4) SiH ₄ , TiCl ₄ and N ₂ are mixed in the gas mixing chamber; the pressure of each gas at the inlet of the gas mixing chamber is equal, and the pressure is kept between 111325-131325Pa; 5) The molar concentration of each substance in the total reaction gas: a) SiH ₄ : 0.33-5%; b) TiCl ₄ : 0.33-1.67%; c) SiH ₄ : TiCl ₄ molar ratio: 1-3; 6) The growth system is a quartz tube reactor, and the pressure of the growth system is 101325-121325Pa; 7) The glass substrate is placed in a quartz tube reactor. The temperature of the glass substrate is 690-750 ° C. The mixed gas of SiH ₄ , TiCl ₄ and N ₂ is transported to the glass substrate for reaction. The reaction time is 30-300 seconds. A titanium silicide film layer is first formed on the substrate, and then high-density silicide nanowires are formed on the metal silicide film; 8) The exhaust gas is discharged after absorption treatment. 2. A method for preparing titanium silicide nanowires by chemical vapor deposition according to claim 1, characterized in that: said thin film is Ti ₅ Si ₃ , TiSi ₂ or a composite of Ti ₅ Si ₃ and TiSi ₂ . 3. A method for preparing titanium silicide nanowires by chemical vapor deposition according to claim 1, characterized in that: said nanowires are TiSi, Ti ₅ Si ₃ or TiSi ₂ . 4. A method for preparing titanium silicide nanowires by chemical vapor deposition according to claim 1, characterized in that: said nanowires are single crystal nanowires. 5. A method for preparing titanium silicide nanowires by chemical vapor deposition according to claim 1, characterized in that: said nanowires have a diameter of 10-40 nm and a length of 0.2-10 μm.

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