JPH01215015A - Formation of single crystal layer - Google Patents

Abstract

PURPOSE:To form a device with high area-efficiency in a short time, by carrying out ion implantation selectively into an insulation substrate surface to form a decomposition region and by generating an epitaxial growth seeds on the decomposition region, and by causing epitaxial growth of a single crystal layer by this growth seeds. CONSTITUTION:An approximately flat silicon oxide film 2 is formed on a silicon substrate 1 as an insulation substrate. Then a resist layer 3 is entirely formed thereon and the resist layer 3 is selectively exposed to form a window part 4. While using the window part 4 as a mask, ion implantation is carried out to change only the surface of the silicon oxide film 2 into a decomposition region 5. After the resist layer 3 is removed by using the silicon substrate 1 having the decomposition region 5 on the silicon oxide film 2 in this way, epitaxial growth seeds are developed on the decomposition region 5 to cause a single crystal layer 6 to grow on the silicon oxide film 2. Consequently, a single crystal layer grows only on the surface of an insulation substrate and, therefore, the area efficiency can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for forming a single crystal layer of single crystal silicon or the like on an insulating substrate. This invention relates to a method for forming a single crystal layer to obtain a silicon-on-insulator structure.

[Summary of the invention]

The present invention provides a method for forming a single crystal layer in which a single crystal layer is epitaxially grown using epitaxial growth seeds.
By generating the epitaxial growth seeds on the altered region formed by ion implantation, this method realizes the formation of a flat single crystal layer with high area efficiency and in a short time.

(Prior Art) One of the Sol formation techniques that is considered promising for the construction of three-dimensional LSIs is a lateral epitaxial growth method using vapor phase growth. This is a method of growing a single-crystal silicon layer on a silicon oxide film using the single-crystal silicon of the substrate as a seed.An example of this technology is ``Nikkei Micro Device.''

° is also described in the July 1985 issue, pages 175-192 (published by Nikkei McGraw-Hill).

By the way, when selective epitaxial growth is performed using multiple seeds with exposed substrates, the grown single crystal layers collide with each other, and the crystallinity of the collided portions deteriorates. to degrade. Therefore, the present applicant has proposed a technique described in Japanese Patent Application Laid-Open No. 62-266824 as a vapor phase growth method to avoid the problem of the collision part, and by using that method, for example, It is also possible to form elements with a wide range of sizes.

[Problem to be solved by the invention]

However, in order to avoid collision areas between single crystal layers, lateral growth over a wide area requires epitaxial growth for a correspondingly long time. That is, as shown in FIG.
The longer the distance mio on the insulating layer 24, the longer the epitaxial growth time to form the single crystal layer 23.

Further, the region used as an element is only the upper region of the insulating layer 24, and the region 25 shown with a dot in the figure is etched off, and the single crystal layer 23 on the upper part of the exposed surface 22, which is a seed, is also used as an element. Therefore, the area in which the single crystal layer can be used as an element has been limited.

Therefore, in view of the above-mentioned technical problems, it is an object of the present invention to provide a method for forming a single crystal layer that can form an element efficiently in terms of area in a shorter time.

[Means to solve the problem]

In order to achieve the above object, the method for forming a single crystal layer of the present invention includes the steps of selectively implanting ions into the surface of an insulating substrate to form an altered region, generating epitaxial growth seeds on the altered region, and The method is characterized by comprising a step of epitaxially growing a single crystal layer using epitaxial growth seeds.

The insulating substrate may be a silicon substrate on which an insulating layer such as an oxide layer or a nitride layer is formed, or a material such as a glass substrate 9 ceramic substrate or a plastic substrate having desired characteristics can be used. The above ion implantation can be performed using, for example, silicon as a dopant, and is not limited to silicon, but can also use, for example, nitrogen, which can form an altered region that becomes a seed for crystal growth. The above-mentioned altered region is formed selectively depending on the element, and in order to prevent crystal growth from becoming polycrystalline, it is preferable to form the affected region narrowly, for example. Furthermore, epitaxial growth seeds are generated on the above-mentioned altered region. In order to epitaxially grow a single crystal layer using this epitaxial growth seed, it is necessary to control the overall pressure, to keep the partial pressure of a gas such as H (1) high during epitaxial growth, which has the property of removing the growing layer, and to control the epitaxial growth. It is also possible to perform an operation such as increasing the partial pressure of the gas only in the initial stage.

[Effect]

By selectively implanting ions into the surface of the insulating substrate, an altered region is formed, and the surface of the insulating substrate covering the altered region has a different surface formation property for crystal growth than the surface of the region where ions are not implanted. Epitaxial growth species are generated from the altered region. Then, by continuing epitaxial growth, a single crystal layer will spread on the insulating substrate from the epitaxially grown seed.

〔Example〕

Preferred embodiments of the present invention will be described with reference to the drawings.

This example is a method for easily forming a single crystal layer on an insulating film (silicon oxide l1l) using ion implantation, and is a method for obtaining a single crystal layer in a short time and with area efficiency. .

The process will be explained in the order of steps with reference to FIGS. 1A to 1C. First, as shown in FIG. form 2.

Next, as shown in FIG. 1, a resist layer 3 is formed on the entire surface, and this resist layer 3 is selectively exposed to form a window portion 4. Here, the window portion 4 can be formed by opening a region corresponding to the element to be formed after forming the single crystal layer, and the interval is such that the region where the single crystal layers collide with each other does not correspond to a channel region, etc. It is preferable to form the window portion 4 while selecting. Further, the size of the window portion 4 is preferably a narrow region in which the layer formed by epitaxial growth does not become polycrystalline.
The planar shape of is not limited, and may be circular, rectangular, or square in shape.

Then, ion implantation is performed using this window portion 4 as a mask. In this ion implantation, for example, silicon is used as a dopant and the silicon is implanted into the surface of the silicon oxide film 2. The implantation energy of this ion implantation can be made sufficiently weak. It suffices if the energy is sufficient to make only the altered jl region 5.

After removing the resist layer 3 using the silicon substrate l in which the altered region 5 is formed on the silicon oxide film 2, as shown in FIG. Form layer 6.

The formation of the single crystal layer 6 is, for example, SiH4+HC1 or S i Hz C1t +HCj! This can be carried out by selective epitaxial growth using the above-described epitaxial growth method, and epitaxial growth seeds are generated in the altered region 5 to grow single crystal N6 on the silicon oxide film 3.

The single crystal N6 formed by the above steps is not a silicon substrate as a seed, but a grown single crystal layer 6.
The entire structure is formed on silicon oxide M2. Therefore, there is no need to separate it from the substrate, etc., and the area used as an element can be expanded to improve area efficiency.

In addition, since the entire single crystal layer 6 can be used in the SO2 structure, for example, the center of the element can be used as the altered region 5.
If this corresponds to the above, the single crystal layer 6 can be formed in about half the time of the conventional method, and wasteful areas that would be etched off (area 25 in FIG. 2 and the area above the exposed part 22)
Since the time required to form the single crystal layer can be saved, the time required to form the single crystal layer can be shortened.

In addition, as elements become three-dimensional and have higher performance, single-crystal layer 6
Even when the silicon oxide film 2 becomes thinner, the altered region 5 remains the same as the silicon oxide film 2.
It has a substantially flat surface that is common to the surface of , and flatness is not a problem.

In the above embodiments, silicon was used as the dopant, but nitrogen or the like may also be used as the dopant. Also,
S iHa +HC1 or 5il(, C1, +IIcj
! Various partial pressures of these gases can be controlled according to their vapor phase growth, and the insulating substrate is not limited to the silicon oxide film 2, but may be another insulating film.

Further, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the gist thereof.

〔Effect of the invention〕

In the method for forming a single crystal layer of the present invention, since the single crystal layer is grown directly by utilizing the altered region on the surface of the insulating substrate, the single crystal layer grows only on the surface of the insulating substrate.
The area efficiency will be improved. Furthermore, by associating the above-mentioned altered region with the position where the element is formed, it is possible to shorten the epitaxial growth time.
Since the area to be etched off is also reduced, a shorter processing time is also possible.

[Brief explanation of the drawing]

1A to 1C are process cross-sectional views for explaining an example of the method for forming a single crystal layer according to the present invention according to the steps, and FIG. 2 is a technical diagram of the conventional method for forming a single crystal layer. FIG. 3 is a cross-sectional view for explaining the problem. l...Silicon substrate 2...Silicon oxide film 3...Resist layer 4...Window portion 5...Altered region 6...Single crystal layer Patent applicant Akira Ichichi, Patent attorney representing Sony Corporation (2 others)

Claims (1)

[Claims] Consisting of a step of selectively implanting ions into the surface of an insulating substrate to form an altered region, and a step of generating epitaxial growth seeds on the altered region and epitaxially growing a single crystal layer using the epitaxial growth seeds. Method of forming a single crystal layer.