JPH069025Y2 - Compound semiconductor single crystal manufacturing equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to a compound semiconductor single crystal manufacturing apparatus, and more particularly to a gallium arsenide semiconductor single crystal manufacturing apparatus.

[Prior Art] When growing a single crystal of a compound semiconductor such as a gallium arsenide (GaAs) semiconductor, various methods are used, and one of them is a zone melting method.

FIG. 4 shows a sectional view of a zone melting apparatus used for growing a GaAs single crystal, 1 is a quartz tube, 2 is a quartz boat,
Reference numeral 3 is GaAs before melting, 4 is a melt zone of GaAs, 5 is a seed crystal, 6 is arsenic (As), 7 is a high temperature furnace, 8 is a melt forming furnace for forming the melt zone 4, and 9 is a solid solution. An interface control furnace 10 that controls the temperature of the interface is a low temperature furnace that heats As.

In the figure, a quartz boat 2 containing Ga2000g and a seed crystal 5 is arranged at one end in a quartz tube 1, and As22 is arranged at the other end.
00g is placed and the inside of the quartz tube 1 is sucked into a vacuum at a pressure of 5 × 10 ⁻⁶ Torr or less for 1 hour or more to seal off, and then the temperature of the low temperature furnace 10 is set to 610 ° C. Then, As arranged on the low temperature furnace 10 side evaporates, and the internal pressure of the quartz tube 1 becomes the vapor pressure of As.
A synthetic reaction of As is performed. Next, when the temperature of the melt forming furnace 8 is raised to 1260 ° C., a part of GaAs is melted to form a melt zone (melt zone) 4.

FIG. 2 shows the temperature distribution when GaAs is melted. The horizontal axis shows the melt zone position X, and the vertical axis shows the temperature in the furnace (T ° C.). The temperature characteristics in the above case are as shown by the curve A in the figure. At this time, the single crystal was grown at a GaAs melt zone width of 100 to 200 mm and a growth rate of 2 to 7 mm / hour.

[Problems to be Solved by the Invention] As a result of growing a GaAs single crystal by using the apparatus shown in FIG. 4 as described above, the temperature characteristic is as shown by the curve A in FIG. 3 and the temperature gradient is relatively large. Although it is shown that the temperature is large, this is because the heat of the melt forming furnace 8 flows toward the interface control furnace 9 and the temperature gradient near the solid-liquid interface becomes large, which increases the convection of the melt. As a result, the solid-liquid interface became uneven toward the melt, and a phenomenon that prevented good growth of GaAs single crystal occurred.

An object of the present invention is to provide a compound semiconductor single crystal production apparatus which prevents the heat flowing from the melt forming furnace to the interface control furnace and stabilizes the solid-liquid interface to grow a high-purity single crystal. is there.

[Means for Solving the Problems] The present invention stabilizes the solid-liquid interface by preventing heat transfer from the melt forming furnace to the interface controlling furnace between the melt forming furnace and the interface controlling furnace. It is characterized by the provision of a heat radiation shielding plate for growing a single crystal with high purity, and the aim is to achieve a high quality single crystal.

[Operation] In the compound semiconductor single crystal production apparatus of the present invention, when a GaAs single crystal is grown using the zone melting apparatus,
The heat radiation shield plate is installed between the melt forming furnace that forms the melt zone and the interface control furnace that controls the temperature of the solid-liquid interface in contact with the melt zone, and is radiated from the melt forming furnace to the interface control furnace. Since the heat transfer is prevented, the temperature gradient at the solid-liquid interface becomes gentle and a high-purity single crystal can be stably grown.

[Embodiment] An embodiment of the present invention will be described below with reference to the drawings.
FIG. 1 is a sectional view showing an embodiment of the compound semiconductor single crystal manufacturing apparatus of the present invention, and FIG. 2 is a side sectional view of FIG. 1 seen from the side. Although these figures are almost the same as the case of FIG. 4, the difference is that the heat radiation shielding plate 11 is provided.

In the case of the present embodiment, by providing the heat radiation shield plate 11, the radiant heat radiated from the melt forming furnace 8 to the interface control furnace 9 is cut off, so that the temperature characteristic becomes as shown by the curve B in FIG. The temperature gradient at the solid-liquid interface X ₀ is 0.5 ° C / cm, which is 1/2 of 1 ° C / cm in the case of the curve A in the figure, and the solid-liquid interface becomes convex on the melt side. A pure single crystal could be obtained. The GaAs single crystal obtained in this case is Ga, A
Under the same conditions as in FIG. 4, the amount of s was 4.1 kg, and a low dislocation crystal having a dislocation density of 10 ⁴ cm ⁻² or less on both the seed crystal side and the crystal tail could be obtained.

A heat insulating material is used as the material of the heat radiation shielding plate,
In addition, silicon carbide (SiC), aluminum oxide (Al
₂ O ₃ ), ceramics such as aluminum azide (AlN) may be used.

Further, it is best to use a cooling plate having a water cooling function, since the temperature gradient near the solid-liquid interface can be made almost zero, and an extremely stable interface can be formed.

[Effect of the Invention] As described above, according to the present invention, the following effects can be obtained.

(1) By using a heat radiation shield plate, the solid-liquid interface can be stabilized during the growth of GaAs single crystal, and a high-purity single crystal can be obtained.

(2) As compared with the horizontal Bridgman method (HB method) and the temperature gradient method (GF method), it is possible to obtain a dopant distribution having a uniform concentration in the crystal length direction, and reduce variations in characteristics between wafers. be able to.

(3) It can be applied particularly effectively when a dopant having a small segregation coefficient is used such as a crystal doped with chrome (Cr).

[Brief description of drawings]

FIG. 1 is a sectional view of a zone melting apparatus showing an embodiment of the compound semiconductor single crystal production apparatus of the present invention, FIG. 2 is a side sectional view of FIG. 1, FIG. 3 is a temperature distribution characteristic diagram, and FIG. FIG. 4 is a cross-sectional view of a conventional device. 1: Quartz tube, 2: Quartz boat, 3: GaAs, 4: Melt zone, 5: Seed crystal, 6: As, 7: High temperature furnace, 8: Melt forming furnace, 9: Interface control furnace, 10: Low temperature Furnace, 11: heat radiation shielding plate.

Claims (1)

[Scope of utility model registration request] 1. A melt forming furnace and an interface control furnace for heating a quartz boat, wherein a quartz boat having a raw material placed at one end and a volatile constituent element at the other end are arranged around the quartz pipe. A dual electric furnace comprising a high-temperature furnace having and a low-temperature furnace for heating the volatile constituent elements is provided, a melt zone is formed in the quartz boat, and the melt zone is moved while moving. In a compound semiconductor single crystal manufacturing apparatus for growing crystals, a solid-liquid interface is provided between the melt forming furnace and the interface control furnace by preventing heat transfer radiated from the melt forming furnace to the interface control furnace. An apparatus for producing a compound semiconductor single crystal, which is provided with a heat radiation shielding plate for stabilizing the.