JPH07302766A - Vapor growing method - Google Patents

Abstract

PURPOSE:To enable the attainment of the coated amount to a specific level in the coating step to be judged by judging the terminal of the coating step from the surface temperature of a substrate mounting member in the coating step. CONSTITUTION:A substrate mounting member mounted with an InP substrate is arranged in a crystal growing chamber while feeding PH3 in net volume of 100cc to the growing chamber to keep the substrate mounting member at the growing temperature (650 deg.C) and after the stabilization of the temperature, AsH3, TMI and TEG in the flow rate corresponding to the composition of an InGaAs film are led in for the time when the film grows about 1mum. Later, after the substrate mounting member reaches the room temperature, the InP substrate after growing the epitaxial film is taken out to measure the PL wavelength and the film thickness thereof as well as the surface temperature with the emissivity of a radiation thermometer fixed at 0.4. Through these procedures, the attainment of the specific coating amount of the film in the coating step can be judged regardless of the film composition so that the needless decision of the coating amount by preliminary experiment in every alteration of the film composition may be eliminated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vapor phase growth method for crystals and further to a metal organic chemical vapor deposition (MOCVD) method, and relates to a technique useful when applied to a substrate mounting member of a vapor phase growth apparatus, for example. The substrate mounting member includes a so-called susceptor, tray, etc., and is used to mount the substrate with the back surface of the substrate in direct contact with the front surface thereof.

[0002]

2. Description of the Related Art Generally, when an epitaxial film is grown on a substrate by a vapor deposition method such as MOCVD,
It is done as follows. That is, a substrate is placed on a substrate placing member such as a susceptor or a tray, and the substrate is placed in the crystal growth chamber. While keeping the substrate placing member at a temperature at which the source gas can be decomposed, the raw material is placed in the crystal growing chamber. Introduce gas. At that time, there is a method of cleaning the substrate mounting member for each growth from the viewpoint of keeping the condition for each growth constant, but the reproducibility is not always obtained and the productivity is lowered. The present applicant has proposed a method of coating a desired amount in advance (Japanese Patent Application No. 05-310545). The desired coating amount is the minimum coating thickness that does not change the characteristics of the thin film grown on the substrate during vapor phase growth even if it is coated more. In addition,
The surface of the substrate mounting member, except the region on which the substrate is placed, remains covered during vapor deposition.

[0003]

However, there is a problem in that the desired coating amount must be determined in advance by experiments.

[0004]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to make it possible to determine that a desired coating amount has been reached (end point) during coating of a coating.

That is, according to the present invention, the raw material gas is introduced into the crystal growth chamber to vapor-deposit a thin film on the surface of the substrate placed on the substrate mounting member, after the substrate mounting member is cleaned in advance. In the method of coating the surface of the substrate mounting member excluding the region on which the substrate is mounted with a coating having the same or similar characteristics as the thin film to be grown on the substrate, the substrate in the coating step. It is intended to provide a vapor phase growth method characterized by determining the end point of the coating step from the surface temperature of a mounting member.

The present invention also provides a vapor phase growth method characterized in that the surface temperature of the substrate mounting member is measured by a radiation thermometer.

First, the present inventors focused on the surface temperature of the substrate mounting member (+ coating film) during the coating process.

A radiation thermometer is generally used as a means for measuring the surface temperature. When measuring with a radiation thermometer, it is necessary to clarify the emissivity of the substance to be measured. However, since the coating film as a target in the present invention is a compound composed of three or more elements and is a polycrystal, the emissivity varies depending on the composition, the smoothness of the surface, etc.,
It has been considered difficult to measure temperature with a radiation thermometer.

However, the present inventors have considered that the absolute value of the temperature is not always necessary. Therefore, the emissivity was fixed to an arbitrary value, and the progress of coating and the change of the display temperature (not absolute temperature) of the radiation thermometer and the characteristics of the obtained epitaxial film at that time were examined. As a result, it was found that there was a strong correlation between the change of the display temperature of the radiation thermometer and the change of the characteristics of the epitaxial film, and the temperature was stable and the characteristics were stable at the same time.

Specifically, under a general growth condition by the MOCVD method, an In ₀ .
_{73 Ga 0. 27 AS 0.} 61 P 0. 39 film (PL (photoluminescence)
A wavelength of 1.3 μm) was epitaxially grown. Note that II
Trimethyl indium (
TMI) and triethylgallium (TEG) were used, and arsine (AsH ₃ ) and phosphine (PH ₃ ) were used as source gases for the group V elements.

First, the InP substrate was placed on the cleaned and baked substrate placing member and placed in the crystal growth chamber. Originally, a so-called dummy substrate is placed at the time of coating,
The original substrate was used to confirm the relationship between the characteristics of the epitaxial film, the coating amount, and the temperature. While passing PH ₃ into the net 100 cc growth chamber, the substrate mounting member was grown at the growth temperature (650 ° C,
Measure the backside of the substrate mounting material with a thermocouple. ) Temperature rise, hold,
After the temperature of the substrate mounting member stabilizes, the above InGaASP
A flow rate of AsH ₃ , TMI and TEG corresponding to the composition of the film was introduced for the time during which the film was grown to about 1 μm.

Then, the introduction of TMI and TEG was stopped,
While cooling the substrate mounting member, the introduction of AsH ₃ and PH ₃ was stopped, and after reaching room temperature, the InP substrate after the epitaxial film growth was taken out from the growth chamber, and its PL wavelength and film thickness were measured. For the surface temperature, the emissivity of the radiation thermometer
It was fixed at 0.4 and measured.

The result of repeating the above process 10 times is shown in FIG.
Shown in. From the third time, the PL wavelength of the epitaxial film was 1.3.
Stable to μm and the display temperature of the radiation thermometer is 610 ℃
Stabilizes at. Therefore, it can be seen that it can be applied to actual growth from the third time when the display temperature of the radiation thermometer becomes stable.

[0014]

EXAMPLES Examples of the present invention will be described below. First, the dummy substrate was placed on the washed and baked substrate placing member and placed in the crystal growth chamber. While passing PH ₃ to the net 100 cc growth chamber substrate placement member the growth temperature (650
Measure the backside of the substrate mounting material with a thermocouple at ℃. ) The heated, held, the temperature of the substrate mounting member is stably, In _{0. 73} Ga _{0.
27 AS 0. 61 P 0.} 39 film flow AsH ₃ that corresponds to the composition of the (PL wavelength 1.3 .mu.m), introducing TMI and TEG continued to grow. For surface temperature, use the emissivity of the radiation thermometer.
It was fixed at 0.4 and measured.

The relationship between the coating time and the temperature indicated by the radiation thermometer at this time is shown in FIG. From this figure, it can be seen that the radiation thermometer display temperature is stable after the coating time of 120 minutes.
In the above experiment, in order to confirm the stability of the temperature indicated by the radiation thermometer, the coating time was up to 200 minutes, but the coating was grown again under the same conditions, the temperature indicated by the radiation thermometer was measured, and the temperature change in 20 minutes When the coating temperature was 3 ° C or less, the coating growth was terminated at 140 minutes, and the InP substrate with the above composition was grown using the InP substrate instead of the dummy substrate.
A film having a desired composition could be grown from the first time.

[0016]

According to the present invention, it is possible to judge that the desired coating amount has been reached (end point) during coating of the coating film regardless of the composition of the coating film. It is effective in reducing costs because it is possible to eliminate waste such as determining.

[Brief description of drawings]

FIG. 1 is a diagram showing the relationship between the number of times a film is grown and its PL wavelength.

FIG. 2 is a diagram showing a relationship between a coating time and a temperature indicated by a radiation thermometer.

Claims (2)

[Claims] 1. The substrate is previously cleaned after the substrate mounting member is washed before vapor-depositing a thin film on the surface of the substrate mounted on the substrate mounting member by introducing a source gas into the crystal growth chamber. A method of coating a surface of a mounting member, excluding a region on which the substrate is mounted, with a coating having the same or similar characteristics as a thin film to be grown on the substrate, wherein the substrate mounting member in the coating step. A vapor phase growth method, characterized in that the end point of the coating step is determined from the surface temperature of the. 2. The vapor phase growth method according to claim 1, wherein the surface temperature of the substrate mounting member is measured by a radiation thermometer.