JPH0796477B2 - Vapor growth method and apparatus - Google Patents

Description

DETAILED DESCRIPTION [Overview] A vapor phase growth method for a compound containing mercury as one of the constituent elements such as mercury cadmium tellurium and a vapor phase growth apparatus used directly for carrying out this method.

The vapor of mercury, which is one of the constituent elements, is supplied using a bubbler, and the temperature from the bubbler to the reaction region is set higher than the bubbler temperature (lower than the decomposition temperature of other substances accompanying it). The mercury vapor pressure in the reaction region can be accurately controlled by controlling it to prevent it from dripping into mercury droplets on the way to obtain a desired mixed crystal ratio.

[Industrial application field]

The present invention relates to a vapor phase growth method for a compound containing mercury as one of constituent elements such as mercury cadmium tellurium and a vapor phase growth apparatus used directly for carrying out this method. In particular, the present invention relates to an improvement in which the mercury vapor pressure in the reaction region can be accurately controlled and the mixed crystal ratio of mercury can be accurately controlled.

[Conventional technology]

FIG. 2 shows a vapor phase epitaxy apparatus that has been widely used as a vapor phase epitaxy apparatus used for implementing the vapor phase epitaxy method of a compound containing mercury as one of the constituent elements such as mercury cadmium tellurium. Reference numeral 1 is a reaction tube made of quartz glass, 2 is a substrate support device made of graphite, which supports a substrate 3, and 4 is an RF coil for controlling a reaction region temperature. Reference numeral 5 is a mercury reservoir and 6 is a mercury evaporation heater. Reference numeral 7 denotes a vapor phase material supply device, which supplies a mixed gas of, for example, dimethylcadmium and diethyl tellurium when the mercury cadmium tellurium layer is grown. In this case, in the reaction region, dimethylcadmium is heated to 350 ° C to 360 ° C and reacts with hydrogen to decompose into cadmium radicals and methane, while diethyl tellurium is heated to 350 ° C to 360 ° C to generate hydrogen. Reacts with and decomposes into tellurium radicals and ethane, and these radicals react with mercury to produce mercury cadmium tellurium.

[Problems to be solved by the invention]

In the conventional vapor phase growth method using the above-described conventional vapor phase growth apparatus, the temperature of the mercury reservoir cannot be accurately controlled, and therefore, the vapor pressure of mercury in the reaction region can be accurately controlled. However, there is a drawback that the mixed crystal ratio of mercury in the grown mercury-cadmium-tellurium layer cannot be controlled accurately.

The object of the present invention is to eliminate this drawback, to precisely control the vapor pressure of mercury in the reaction region, to accurately control the composition ratio of the material gas in the reaction region to a desired value, A vapor phase growth method capable of growing a material having a mixed crystal ratio, and a vapor phase growth apparatus used directly for carrying out the method.

[Means for solving problems]

Among the above objects, a means for achieving the first object is a vapor phase growth method for producing a compound semiconductor containing mercury and one of organometallic compounds as starting materials, wherein the starting materials are the above-mentioned starting materials. Of the above, mercury is vaporized outside the reactor at a temperature corresponding to the predetermined saturated vapor pressure of mercury and supplied to the mercury vapor supply pipe, and in this mercury vapor supply pipe, the temperature corresponding to the saturated vapor pressure of mercury. After being heated to a higher temperature, it is fed to the reaction zone, while among the starting materials mentioned above, the organometallic compounds are fed to the reaction zone at a temperature lower than the decomposition temperature of this material and the This is a vapor phase growth method in which an optimum amount is supplied to the reaction region to cause mutual reaction.

Further, the means for achieving the second object is a vapor phase growth apparatus for growing a layer of a compound containing mercury as one of the constituent elements, and the vapor phase growth apparatus includes a bubbler (8) for vaporizing mercury. , A mercury vapor supply pipe (9) for supplying mercury vapor from the bubbler (8) to the reaction region, a temperature control means (10) for controlling the temperature of the mercury vapor supply pipe (9), and an element other than mercury. The vapor phase growth apparatus is provided with a vapor phase material supply means (7) for supplying gas.

[Action]

In the present invention, since the bubbler is used to supply the mercury vapor, it is easy to supply the mercury vapor at its saturated vapor pressure, and the temperature from the bubbler to the reaction region is controlled. Therefore, a sufficient amount of mercury vapor is supplied to the reaction region at a temperature higher than the temperature corresponding to the saturated vapor pressure of mercury without dripping on the way, while the above temperature control is accompanied by other substances. Therefore, the mixed crystal ratio can be controlled to a desired value.

〔Example〕

Hereinafter, a vapor phase growth method and apparatus according to an embodiment of the present invention will be further described with reference to the drawings.

See FIG. 1. FIG. 1 is a structural diagram of a vapor phase growth apparatus according to an embodiment of the present invention. In the figure, 1 is a reaction tube made of quartz glass, and 2
Is a substrate supporting device made of graphite, which supports the substrate 3, and 4 is an RF coil for controlling the reaction region temperature.

Reference numeral 8 is a bubbler for vaporizing mercury according to the gist of the present invention. Mercury is put in a container 81, and a desired temperature, for example, 200 ° C. to 230 ° C. is controlled by a heater 82. Reference numeral 83 is a hydrogen gas supply device, which forms hydrogen gas into bubbles and supplies the hydrogen gas into mercury to vaporize the mercury. Reference numeral 9 denotes a mercury vapor supply pipe according to the gist of the present invention, the temperature of which is controlled by the temperature control means 10. Reference numeral 7 denotes a vapor phase material supply device, which supplies a mixed gas of, for example, dimethyl cadmium and diethyl tellurium when the mercury cadmium tellurium layer is grown.

The temperature control by the temperature control means 10 is made slightly higher than the temperature corresponding to the saturated vapor pressure of mercury, in other words, slightly higher than the temperature of the bubbler 8 and maintained at, for example, 240 ° C to 250 ° C. In addition, the upper limit of temperature control is set to the decomposition temperature of the accompanying substances (dimethylcadmium and diethyl tellurium in this example). Therefore, the mercury vapor is supplied to the reaction region in a desired amount controlled by the bubbler 8 without dripping on the way. On the other hand, the accompanying substances (dimethylcadmium and diethyl tellurium in this example) are controlled at a temperature slightly lower than the decomposition temperature, so that the desired amount is supplied to the reaction region without decomposition during the process. In this example, dimethylcadmium reacts with hydrogen to decompose into cadmium radicals and methane in the reaction region on the substrate 3 kept at 350 ° C to 360 ° C, while diethyl tellurium reacts with hydrogen. It decomposes into tellurium radicals and ethane, and these radicals react with mercury to grow a substance having exactly the desired mixed crystal ratio, such as a mercury-cadmium tellurium layer.

〔The invention's effect〕

As explained above, in the present invention, the bubbler for vaporizing mercury, the mercury vapor supply pipe for supplying the mercury vapor from the bubbler to the reaction region, the temperature control means for controlling the temperature of the mercury vapor supply pipe, and the mercury vapor In vapor phase growth of a compound having mercury as one of the constituent elements using a vapor phase growth apparatus provided with a vapor phase material supply means separate from the supply pipe, the vapor of mercury among the constituent elements is used. Has a temperature slightly higher than the temperature corresponding to the saturated vapor pressure of mercury (having a temperature slightly higher than the bubbler temperature), and among the constituent elements, other substances are lower than the decomposition temperature of this other substance. Since it is said that the mercury vapor vaporized by the bubbler is supplied to the reaction region at a desired amount controlled by the bubbler without being dripping in the middle, while being supplied to the reaction region at a temperature, You Substances, the desired amount, since it is fed to the reaction zone, it is possible to grow a layer of material having exactly the desired mixed crystal ratio.

[Brief description of drawings]

FIG. 1 is a structural diagram of a vapor phase growth apparatus according to an embodiment of the present invention. FIG. 2 is a structural diagram of a conventional vapor phase growth apparatus. 1 ... Reaction tube, 2 ... Substrate support device, 3 ... Substrate, 4 ... RF coil, 5 ... Mercury reservoir, 6 ... Heater, 7 ... Vapor phase material supply device, 8 ... Bubbler, 81 …… Container, 82 …… Heater, 83 …… Hydrogen gas supply device, 9 …… Mercury vapor supply pipe, 10 …… Temperature control means.

Claims (2)

[Claims] 1. A vapor phase growth method for producing a compound semiconductor containing mercury and one of organometallic compounds as starting materials, the compound semiconductor containing mercury as one of the constituent elements. It is vaporized at a temperature corresponding to the saturated vapor pressure of mercury and supplied to the mercury vapor supply pipe, heated in the mercury vapor supply pipe to a temperature higher than the temperature corresponding to the saturated vapor pressure of mercury, and then supplied to the reaction region. Among the starting materials, the organometallic compound is supplied to the reaction zone at a temperature lower than the decomposition temperature of the material, and an optimal amount of each of the starting materials is supplied to the reaction zone to react with each other. A vapor phase growth method characterized by the above. 2. A vapor phase growth apparatus for growing a layer of a compound containing mercury as one of the constituent elements, wherein the vapor phase growth apparatus vaporizes mercury at a temperature corresponding to a predetermined saturated vapor pressure of mercury. A bubbler (8), a mercury vapor supply pipe (9) for supplying mercury vapor from the bubbler (8) to the reaction region, and a temperature control means (10) for controlling the temperature of the mercury vapor supply pipe (9). A vapor phase material supply means (7) for supplying a gas of an element other than mercury, and the vapor phase growth apparatus.