JPS58209163A - Thin-film transistor - Google Patents

Abstract

PURPOSE:To obtain the transistor of high mobility by separating and extracting silica group glass of low alkali from phase-splitting glass at a temperature lower than a melting temperature of normal quartz glass by utilizing a phase-splitting phenomenon of glass and forming the thin-film transistor onto said silica group glass while using said silica group glass as a substrate. CONSTITUTION:SiO2-B2O3-Na2O Group glass in which the phase-splitting phenomenon is easy to be generated extremely is thermally treated at a temperature of 500-600 deg.C, and phase-separated into a SiO2 component and a B2O3-Na2O group component. A B2O3-Ma2O group component is separated and extracted through immersion in diluted hydrochloric acid at a temperature of approximately 90 deg.C, and the silica group glass, the SiO2 component therein is approximately 98%, is obtained. Said silica group glass is used as a substrate 1, a polycrystalline Si film 3 is deposited on the substrate through an SiO2 film 2, and P<+> type source and drain regions are formed in the film 3. The whole surface is coated with an SiO2 film 4, an opening is bored, an Al electrode 5 being in contact with these regions is formed, and the film 4 between these regions is also coated with a gate electrode 5.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention activates and transfers a Si-based semiconductor material formed on a glass substrate at high temperature without damaging the substrate.
The present invention relates to a method for manufacturing a thin film transistor with a high degree of #A.

[7 Problems with conventional branch techniques]

The thermal shock resistance of ordinary soda-lime glass and borosilicate glass is generally poor, and even glass with very little alkali has a heat resistance of Δ'11j600'C. When manufacturing gold,
It was difficult to raise the total heat treatment temperature for activation to 600°C or higher. Therefore, activation of the semiconductor material is insufficient, and even when polysilicon is used as the semiconductor material, the particle size is 0.5p or less. On the other hand, if quartz glass is used for the substrate, these drawbacks 1 will be eliminated, but quartz glass has the drawbacks of being expensive and difficult to process.[Objective of the Invention] The present invention improves these drawbacks. Its purpose is to make full use of the phase separation phenomenon of try glass, and to lower the melting temperature by 400 to 500
It is possible to separate and extract a low-alkali silica-based glass from a phase-separating glass at a low temperature and use it as a substrate to obtain a thin film transistor with high mobility. [Summary of the Invention] Used in the device of the present invention As the glass, phase splitting glass is used. For example, SiO, -Bo3-Na,0-based glass is used. This type of glass is extremely susceptible to phase separation, and when heat treated at a temperature of, for example, 500 to 600° C., phase separation easily occurs into a Si component and a '5-Naρ component. B2O3-N with dilute hydrochloric acid at a temperature of about 90℃
If the a20 component is eluted, the 5i02 component will be approximately 98
This glass, which can be industrially obtained as a silica-based glass with a grade of be. By using this in place of the silicon wafer of conventional thin film transistors, it is possible to fabricate glass substrate thin film transistors.

〔Effect of the invention〕

Using wood glass as a substrate, S i OH1 polycrystalline silicon is deposited thereon. After P ion implantation, activation or grain growth is performed by performing polycrystalline silicon whole laser or electron beam annealing or zone melting while maintaining the substrate temperature at 700 to 800°C. Using this, the mobility of the P-channel FET can be changed to about 100 to 13 ocr4AIsec.

[Embodiments of the invention]

Example 1 Polysilicon P-chan-n attached on glass in the drawing
The cross-sectional structure of the el, kl gate F'FJT is shown. Glass is extracted from phase splitting glass (7.
ift 75% Btu3204 Using borosilicate glass with 5% Na2O as a starting material, after heat treatment at 500°C for 2 hours, 5i02 and 'ho3 Na2Q components and 'e 2N-H2
Silica-based glass gold (5i0298) was obtained by elution and extraction with S04, and this glass with a thickness of 0.5 m was annealed and then processed into a plate shape. 5i02 (03μ) Lp-cv on it
Polycrystalline silicon of 0.7 µm was deposited using the D method, and using this as a substrate, P ion implantation was performed under conditions of 130 KeV and 10 A. Then use a 10 WAr laser with a spot diameter of 1
The entire surface was annealed at a substrate temperature of 700° C. for 10 minutes, and this was used as a substrate to fabricate a P-channel FgTk. W/L = 16/8 (Enhanc
field effect hole mobility 1d130d for
/Vsec, Vth = -1.5V.

Note that there was no wafer damage during heat treatment, activation, laser annealing, etc. 3. Example 2 Same as Example 1, P-ch annetA L game)
, F'ET was produced. As the substrate glass, high silica glass was obtained by extracting the silica component from phase splitting glass. That is, 5i0270%B20327chi Nano 3
% borosilicate glass was used as a raw material, and after heat treatment at 600°C for 1 hour, phase separation was performed. This was eluted with a 3N-HcL solution at 90°C to extract the silica component. 5iO297% after extraction
The glass was remelted, annealed, and then processed into a plate shape. This was used as a substrate, and K 5i02 (0.3μ) was applied thereon, and polycrystalline silicon 0.7μ was deposited on the 5i02 by the LP-CVD method. A total of 130 keys of P ion implantation into polycrystalline silicon.

1 The test was carried out under conditions of 10°C.

Thereafter, the entire surface was annealed using a 5WXYAG laser at a substrate temperature of 750° C. and a spot diameter of 80 μm to grow a single crystal. The crystal grain size was approximately 10μ. P-channel on this board
etFET (W/L=16/8') enhance
The field effect hole mobility of ment type is 120 crn/
V, see Vth=-1.7V. Note that there was no damage to the substrate during heat treatment, activation, and annealing.

Table 1 shows the comparison of the physical properties of this substrate glass with that of silica glass.As mentioned above, this substrate can be synthesized at a much lower temperature than silica glass, the cost is less than half that of silica glass, and the physical properties are also comparable to those of silica glass. It is similar to this, and if an ordinary thin film transistor is made using this glass, the substrate will not be damaged or bent at high temperatures when the semiconductor material is activated by heating annealing, and a high-vibration FET can be obtained, making it an excellent glass for industrial use. It can be said to be a substrate thin film transistor.

[Brief explanation of drawings]

The drawing shows glass substrate P-channel A l Kate F
'ET is a cross-sectional view. In the figure, 1 is an eluted glass substrate, 2 is a SiO mushroom film, 3 is a polycrystalline silicon film, and 4 is a Sin
, 5 are kt electrodes.

Claims (2)

[Claims] (1) A thin film transistor formed on a silica-based glass substrate synthesized using phase separation development. (2) Regarding the substrate, glass, silicon oxide JE-6
- The thin film transistor described in Patent No. 1, characterized in that it is comprised of: