JPH065484A - Manufacture of thin film semiconductor substrate - Google Patents

Abstract

PURPOSE:To form a silicon thin film of an excellent quality, by sticking a semiconductor single crystal film having a specified thickness on at least one main surface of a quartz substrate. CONSTITUTION:By implanting oxygen ions from one main surface of a silicon wafer 1, an oxygen ion implanted layer 2 is formed under a silicon thin film 3 so as to leave the film 3 of 0.1mum in thickness. Next by annealing, the ion implanted layer 2 is activated, and a silicon oxide film of 0.1-0.3mum in thickness is formed as an ion implanted active layer 4, which silicon oxide film is simultaneously turned into a single crystal film excellent in crystallinity. The surface of the silicon thin film 3 of a wafer 9 is closely brought into contact with the main surface of the quartz substrate 5 and heated. The wafer is stuck on the quartz substrate 5 as the result of silanol reaction. Next the other main surface of the silicon wafer 1 is eliminated by chemical etching using saturated aqueous solution of KOH or the like. Thereby a silicon thin film substrate of an excellent quality can be formed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a thin film semiconductor substrate, and more particularly to a method for manufacturing a silicon thin film semiconductor substrate.

[0002]

2. Description of the Related Art Conventionally, silicon on sapphire has been the most general method for manufacturing a thin film semiconductor substrate. That is, it is a method in which a silicon single crystal film is epitaxially grown as heterogeneous epitaxial on one main surface of a sapphire single crystal wafer.

[0003]

However, according to the above-mentioned conventional technique, there are many crystal defects, many interface states between sapphire and silicon, and aluminum, which is a dopant, diffuses into the silicon film.

An object of the present invention is to solve the problems of the prior art and to form a high quality silicon thin film.

[0005]

In order to solve the above problems and to achieve the above objects, the present invention relates to a method for producing a thin film semiconductor substrate, including: (1) at least one main surface of a quartz substrate having a thickness of 0.
Taking a means for sticking a semiconductor single crystal film having a thickness of about 1 micron or less, and (2) Taking a means for forming the semiconductor single crystal film with silicon in (1), and (3)
Oxygen ions are ion-implanted to a depth of about 0.1 micron from one main surface of the silicon single-crystal wafer, and annealed at a high temperature to form the oxygen-ion-implanted layer into a silicon oxide film. Is attached to a quartz substrate by a silanol reaction, and means for chemically etching the silicon layer to the silicon oxide film from the other main surface of the silicon single crystal wafer with a saturated aqueous solution of potassium hydroxide is used, and (4) silicon single crystal Nitrogen ions are implanted to a depth of about 0.1 μm from one main surface of the wafer and annealed at a high temperature, and the one main surface of the silicon single crystal wafer in which the nitrogen ion-implanted layer is a silicon nitride film is formed on the quartz substrate. It is attached to the surface of the silicon single crystal wafer by silanol reaction, and the amount of potassium hydroxide saturated from the other main surface of the silicon single crystal wafer. Taking a means to chemically etch the silicon layer to the silicon nitride film with an aqueous solution,
And (5) Oxygen ions and nitrogen ions are ion-implanted to a depth of about 0.1 micron from one main surface of the silicon single crystal wafer, and annealed at a high temperature to form the oxygen and nitrogen ion-implanted layer into a silicon oxynitride film. Means of chemically adhering the one main surface of the formed silicon single crystal wafer to a quartz substrate by a silanol reaction, and chemically etching the silicon layer from the other main surface of the silicon single crystal wafer to a silicon oxynitride film with a saturated aqueous solution of potassium hydroxide And (6) a silicon single crystal wafer in which boron ions are ion-implanted to a depth of about 0.1 micron from one main surface of a silicon single crystal wafer and annealed at a high temperature to activate the boron ion-implanted layer. The above-mentioned one main surface of a silicon single crystal wafer was attached to a quartz substrate by a silanol reaction. Taking means for chemically etched from the surface of the silicon layer to the boron ion implantation activation layer including a saturated aqueous solution of hydroxide Karyuumu, take measures such as.

[0006]

EXAMPLES The present invention will be described in detail below with reference to examples.

FIG. 1 is a sectional view showing a method of manufacturing a thin film semiconductor substrate according to an embodiment of the present invention in the order of steps. That is,
(A) From the mirror-polished surface of one main surface of the silicon wafer 1 or the mirror surface with a thin silicon oxide film formed, (b) oxygen ions at an acceleration energy of 50 to 100 KeV and 10 ¹⁵
/ Cm ² degrees implanted, leaving a layer of silicon thin film 3 of 0.1 micron thickness, the oxygen under the silicon thin third layer to form an ion implanted layer 2, (c) 1200 ° to 1
The ion implantation layer 2 is activated by annealing in an inert atmosphere at about 300 ° C. for about 1 to 3 hours to form a silicon oxide film as the ion implantation activation layer 4 with a thickness of 0.1 to 0.3 μm. The crystal defects induced by ion implantation in the silicon thin film 3 are also annealed out while being formed to a degree to form a single crystal film having good crystallinity. (D)
Next, the surface of the silicon thin film 3 of the wafer of (c) is brought into close contact with one main surface of the quartz substrate 5 that has been mirror-polished, and the quartz substrate is heated to 800 to 1200 degrees in a hydrogen atmosphere to cause a silanol reaction. 5 and the wafer are attached. (E) Next, the other main surface of the silicon wafer, that is, the back surface is removed by chemical etching using a saturated aqueous solution of KOH or the like. At this time, the quartz substrate 5 and the ion implantation activation layer 4 formed into a silicon oxide film are hardly etched, that is, the etching is automatically stopped at the ion implantation activation layer 4. (F) Next, if necessary, the ion implantation activation layer 4 formed into a silicon oxide film can be removed by etching with hydrofluoric acid or the like.
It is possible to form a thin film semiconductor substrate in which the silicon thin film 3 made of a single crystal having a thickness of 1 micron is attached to one main surface of the quartz substrate 5. The ion-implanted activation layer 4 may be left as it is, or the etching may be stopped halfway to leave a required thickness.

In addition to oxygen ion implantation, nitrogen ion implantation, oxygen and nitrogen ion implantation, and boron ion implantation may be performed on the ion implantation layer 2. In that case, the ion implantation activation layer 4 is made of silicon. Although it is a nitride film, a silicon oxynitride film, or a P ⁺ silicon layer, both act as an etching stop layer, and the silicon nitride film and the silicon oxynitride film form a silicon thin film by etching with phosphoric acid or hydrofluoric acid. Although it can be selectively removed by leaving it, mechanochemical etching needs to be used only in the case of the P ⁺ silicon layer.

Further, the silicon wafer 1 may be another semiconductor wafer, in which case the silicon thin film 3 is used.
Will be another semiconductor thin film.

The semiconductor thin film substrate according to the present invention is used for a TFT, and particularly for a pixel and an XY drive circuit for driving a liquid crystal display body for a liquid crystal television for a high-definition television or a viewfinder of a video camera which requires a high speed operation. It can be used as a TFT.

[0011]

According to the present invention, it is possible to form a high-quality silicon thin film substrate with few crystal defects, few interface states between quartz and silicon, and no diffusion of dopant into the silicon film.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a method of manufacturing a thin film semiconductor substrate according to an embodiment of the present invention in the order of steps.

[Explanation of symbols]

 1 ... Silicon wafer 2 ... Ion implantation layer 3 ... Silicon thin film 4 ... Ion implantation activation layer 5 ... Quartz substrate

Claims (6)

[Claims] 1. At least one main surface of a quartz substrate is 0.1.
A method of manufacturing a thin film semiconductor substrate, characterized in that a semiconductor single crystal film having a thickness of about a micron or less is attached. 2. The method for producing a thin film semiconductor substrate according to claim 1, wherein the semiconductor single crystal film is made of silicon. 3. A silicon single crystal wafer in which oxygen ions are ion-implanted to a depth of about 0.1 μm from one main surface of a silicon single crystal wafer and annealed at a high temperature to form the oxygen ion-implanted layer as a silicon oxide film. Said one main surface of said is adhered to a quartz substrate by a silanol reaction, and the silicon layer is chemically etched from the other main surface of the silicon single crystal wafer to a silicon oxide film with a saturated aqueous solution of potassium hydroxide or the like. The method for producing a thin film semiconductor substrate according to claim 1 and claim 2. 4. A silicon single crystal wafer in which nitrogen ions are ion-implanted to a depth of about 0.1 μm from one main surface of a silicon single crystal wafer and annealed at a high temperature to form the nitrogen ion-implanted layer as a silicon nitride film. The one main surface of the is adhered to a quartz substrate by a silanol reaction, and the silicon layer is chemically etched from the other main surface of the silicon single crystal wafer to the silicon nitride film with a saturated aqueous solution of potassium hydroxide or the like. The method for producing a thin film semiconductor substrate according to claim 1 and claim 2. 5. An oxygen ion and a nitrogen ion are ion-implanted to a depth of about 0.1 micron from one main surface of a silicon single crystal wafer and annealed at a high temperature to form the oxygen and nitrogen ion-implanted layer into a silicon oxynitride film. The one main surface of the made silicon single crystal wafer is attached to a quartz substrate by a silanol reaction, and the silicon layer is chemically etched from the other main surface of the silicon single crystal wafer to a silicon oxynitride film with a saturated aqueous solution of potassium hydroxide. The method for producing a thin film semiconductor substrate according to claim 1 or 2, wherein. 6. A silicon single crystal wafer in which boron ions are ion-implanted to a depth of about 0.1 μm from one main surface of a silicon single crystal wafer and annealed at a high temperature to activate the boron ion-implanted layer. The main surface is attached to a quartz substrate by a silanol reaction, and the silicon layer is chemically etched from the other main surface of the silicon single crystal wafer to the boron ion-implanted activation layer with a saturated aqueous solution of potassium hydroxide or the like. The method for producing a thin film semiconductor substrate according to claim 1 and claim 2.