JPS6046183B2 - Method and apparatus for epitaxial deposition of silicon on a substrate - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for epitaxially depositing silicon on a substrate by a silicon-iodine transport reaction using a reactor.

When silicon is epitaxially deposited on a substrate by a silicon-iodine-transport reaction, the conventional method is to arrange the growth source and the substrate at a certain distance from each other.

In this case, the distance is at most a few millimeters. In this case, it is necessary to arrange special equipment to ensure a temperature profile corresponding to this small distance. The invention provides a silicon deposition method which makes it possible to use equipment customary in semiconductor technology and thus also to use, for example, diffusion furnaces known in diffusion technology to create the temperature range required for the deposition. is the fundamental issue. Furthermore, the method according to the invention should also allow selective silicon deposition, limiting the deposition to unmasked areas of the substrate. To solve this problem, it is proposed, in a method of the type described at the outset, to position the substrate in relation to its height in the reactor in such a way that the desired deposition is obtained. When we refer to height herein, we mean the height above the reference point.

The height relationships shown apply in horizontally or vertically arranged reactors. According to the invention, the substrate is placed in the reactor at a higher level than the growth source.

The degree of precipitation is adjusted by the height position of the substrate within the reactor. The higher the substrate is placed in the reactor, the higher the degree of precipitation will generally be. The reactor is brought to the temperature range required for the deposition, preferably in such a way that the part of the reactor containing the substrate reaches that temperature range first. Advantageously, the iodine source is placed on the same side as the silicon source, which is placed separately from the substrate. The precipitation process is advantageously controlled by the time-related temperature profile.

In this case the temperature is adjusted from the starting temperature to the working temperature. Finally, the temperature is adjusted from the working temperature to the final temperature. According to one embodiment of the invention, at least two temperature zones with different temperatures in the longitudinal direction of the reactor are present in the reactor, one temperature zone being at a temperature of the other in the longitudinal direction of the reactor. The band is actually longer than that.

The substrate is located in the longer temperature zone and the iodine source and silicon source are located in the other temperature zone. For example, the temperature of each temperature range is 500
-1300°C, and the temperature difference between each temperature zone is, for example, 10-500°C. Selective precipitation is obtained by appropriate selection of the pressure within the reactor.

To obtain multiple temperature bands, standard diffusion furnaces commonly used in diffusion technology can be used. For this kind of diffusion furnace, the temperature transition area between different heating zones is well known as 5C77! larger than It is advantageous in the process of the invention to use a closed reactor. The reactor can be arranged horizontally or vertically in the longitudinal direction.
Next, the present invention will be explained in detail based on examples.

In order to obtain an industrially usable precipitation degree using a silicon monoiodide transport system for transporting silicon from the growth source (support 1) to the substrate (support ■) in the gas phase, known methods are used. In this case, the space between both supports under different temperatures is several 10p7n,
~number? Must.

This condition requires special technical configuration. The process according to the invention requires, on principle of industrial application, the use of conventional diffusion furnaces, which are known from numerous applications in the semiconductor field. Diffusion furnaces of this type are characterized by a long, elongated arrangement and make it possible to obtain zones of different temperatures, separated from each other in the longitudinal direction of the furnace, at a low cost. If a longer reactor is used, by arranging the furnace in a long extension and maintaining a constant temperature in each longitudinal zone, a larger quantity of substrates can be processed under finishing conditions. . FIG. 1 shows an apparatus for epitaxially depositing silicon according to the present invention. This device is real! A sealed filter with at least two separately adjustable heating zones, e.g. length 1 TL and diameter 80-1
It consists of a concave reactor 1 and a heating coil 2. Inside the reactor 1 there is a support 3 for a silicon source on which a silicon source 4 is placed, as well as a support 5 for a silicon substrate on which a silicon substrate 6 is placed, and iodine vapor is introduced. FIG. 2 shows the temperature profile in the reactor, ie the relationship between the temperature T and the longitudinal extension position X of the reactor.

According to this temperature course, the silicon source 4 has a length of, for example, 10 to 20 mm.
C7rL and a high temperature zone 7 with a temperature of 900 DEG C., and the substrate 6 is in a low temperature zone 8 with a length of 60 to 80 cm and a temperature of 800 DEG C., for example. Between temperature zones 7 and 8 there are 5 to 3
There is a temperature transition region 9 with a length of 0 cm. The present invention
It is based on the recognition that the position of the substrate in the reactor is of decisive significance for silicon deposition, given the very wide spacing between the silicon source and the substrate provided by the temperature transition zone.

The silicon deposition thus depends very essentially on the height position of the substrate within the reactor, the height position extending upwards.
Three representative substrate locations are shown in FIGS. 3-5. In FIG. 3, the substrate 6 is below the reactor. No silicon precipitation occurs at this location, and the substrate surface is instead corroded. In FIG. 4, the substrate 6 is at a central height position. In this position the substrate has already undergone silicon deposition. Fifth
In the figure, the substrate 6 is in the highest position and significant silicon deposition occurs at this substrate position. Silicon deposition therefore increases with increasing substrate height. 3 to 5 differ only in that the height of the substrate is different.

The spacing between the substrate and the growth source as well as the temperature and pressure within the reactor do not differ in the three cases and therefore remain the same. If selective deposition is desired in the process of the invention, the substrate is partially masked in accordance with the selective deposition and is introduced into the deposition zone at the corresponding height of the reactor.

Furthermore, the total pressure in the reactor must be adjusted so that silicon is advantageously deposited on the unmasked silicon substrate. FIG. 6 shows a semiconductor with an epitaxial layer 10 selectively deposited on a substrate 6. In FIG.

The mask material 11 may be a material commonly used in the semiconductor industry, such as S.
iO2 or Si3N4 can be used.

[BRIEF DESCRIPTION OF THE DRAWINGS] FIG. 1 is a schematic diagram of an apparatus for epitaxially depositing silicon according to the present invention, and FIG. 2 is a graph showing the temperature course in the reaction apparatus.
FIG. 3 is a diagram showing the substrate position, FIG. 4 is a diagram showing another substrate position, FIG. 5 is a diagram showing another substrate position, and FIG. 6 is a cross section showing a part of a semiconductor having an epitaxial layer. It is a diagram. 1... Reactor, 2... Heating coil,
3...Support, 4...Silicon source, 5...
... Support body, 6 ... Substrate, 10 ... Epitaxial layer, 11 ... Mask material.

Claims (1)

[Scope of Claims] 1. A method for epitaxially depositing silicon on a substrate by a silicon-iodine-transport reaction using a reactor, in which the desired deposition is carried out on the substrate in relation to the height of the substrate in the reactor. 1. A method for epitaxially depositing silicon on a substrate, characterized in that the arrangement is such that it is obtained. 2. The method according to claim 1, wherein the substrate is placed at a higher position than the growth source in the reaction apparatus. 3. The method according to claim 1 or 2, wherein the degree of precipitation is adjusted by the height position of the substrate within the reaction apparatus. 4 In an apparatus for epitaxially depositing silicon on a substrate by a silicon-iodine transport reaction using a reaction apparatus, at least two temperature zones having different temperatures in the longitudinal axis direction of the reaction apparatus exist, and one Apparatus for the epitaxial deposition of silicon on a substrate, characterized in that one temperature zone is actually longer in the longitudinal direction of the reactor than the other temperature zone. 5. The apparatus of claim 4, wherein the substrate is placed in the longer temperature zone and the iodine source and silicon source are placed in the other temperature zone. 6. The apparatus according to claim 4 or 5, wherein the temperature of each temperature zone is within the range of 500 to 1300C, and the temperature difference between each temperature zone is 10 to 500C. 7. Apparatus according to any one of claims 4 to 6, wherein the pressure in the reactor is selected such that selective precipitation is achieved. 8. Any one of claims 4 to 7 installed in a conventional diffusion furnace with diffusion technology in order to obtain a plurality of temperature zones, which results in a transition area longer than 5 cm between each temperature zone. Equipment described in Section. 9 Claim No. 4 installing a closed reaction device
The device according to any one of paragraphs 8 to 8. 10. The apparatus according to any one of claims 4 to 9, wherein the distance between the substrate and the growth source is larger than the temperature transition region between each temperature zone. 11. The device according to any one of claims 4 to 10, wherein the substrate is within one temperature band having the temperature gradient.