JPS5891629A - Liquid phase epitaxial growth - Google Patents

Abstract

PURPOSE:To manufacture the epitaxial layer having a little defect, having a favorable quality and having favorable yield by a method wherein a dummy substrate is arranged adhering closely to the side of a substrate for growth on the opposite side with the transferring direction of the substrate for growth, and the substrates are made to come in contact with solutions in order. CONSTITUTION:The substrate 11 for InP growth is set up in a concave 6 of a substrate holding plate 4, and moreover, the dummy InP substrate 10 is set up as to adhere closely to the substrate 11 for growth in the rear of the substrate for InP growth. The substrates are heated to be held at the set temperature, lowering of the temperature is performed by the prescribed cooling temperature, the substrate holding plate 4 is moved in the direction shown with an arrow mark 8 to be transferred to the part under a solution reservoir 10, and the surface of the substrate 11 for growth is made to come in contact with the mixed liquid 12a of In and P. By moving the substrate 11 for growth to the positions of the solution reservoir 10 in order, the epitaxial layers of the plural number can be formed.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing semiconductor crystals by liquid phase epitaxial growth. More specifically, it relates to a horizontal sliding liquid phase epitaxial growth method, that is, a manufacturing method in which crystal growth is performed by mechanically moving a substrate holding plate holding a growth substrate at the bottom of the solution.

Reference numeral 111181 is a cross-sectional view of an example of a liquid phase epitaxial growth port conventionally used in the horizontal sliding #IL phase epitaxial growth method.

As shown in the figure, the conventional growth M boat has a plurality of mutually spaced solution reservoirs 1 (*&). ---
It is expressed as ・−・−・. ), a nine-furnace puto 2, and a substrate holder fE4 movable in a passage 3 extending across the bottoms of these solution reservoirs 1 and having substrate holders 1 and 6.

In the liquid phase epitaxial growth method using this growth l-F, a growth solution 7 (the entire growth solution is represented by 7, and each growth solution is represented as 7a, 7be, 7c) is generally held in a solution reservoir l. Then, the growth substrate 5 is placed in the recess 6 of the substrate holding plate 4. First, the substrate holding plate 4 is placed in the positional relationship shown in Figure 1.

Next, the temperature is maintained at a desired temperature, and then the temperature is lowered at a certain cooling rate.At the same time, the substrate holding plate 4 is slid in the direction of the arrow 8, and the growth substrate 5 is placed under the solution reservoir la. Move the surface of the growth substrate &'5 so that it comes into contact with the growth solution.

As a result, an epitaxial layer is formed with a desired thickness depending on the desired temperature drop range or the contact time between the growth substrate 5 and the growth melt *ya. Hereafter, the substrate is held f in the same manner.
4 and move the growth substrate 5 sequentially to the positions of solution reservoirs lk and lc.
In FIG. 1, three layers are formed.

FIG. 112 shows the conventional liquid phase epitaxial growth method explained in FIG. 1, and shows the positional relationship between the growth solution 7 and the growth substrate 5 during epitaxial growth.

Figure 3 is a diagram of the growth surface of a 50-layer growth substrate manufactured by a conventional method. In the conventional method, when the substrate is moved, the solution is brought onto the growth substrate S through the slight gap between the substrate holding plate 4 and the substrate holding plate 4 shown in Fig. When the next growth solution and the growth substrate come into contact, the growth ratio in the growth solution is not the predetermined one, and the lattice constant of the epitaxial growth layer deviates from the growth substrate, and the b11 overlap structure is not controlled. Inconveniences occur and normal epitaxial growth cannot be performed.

Furthermore, there is a drawback that the solution remains in a portion of the growth substrate 5, at the rear of the growth substrate 50 in the normal movement direction 8, and hardens when the growth is completed. An example of this situation is shown in the third
Shown in the figure. This residual corner portion 9 cannot be manufactured as an element with a predetermined layer thickness and a predetermined composition of crystals of -% tsO, so a large portion of the solution brought in remains. Yield decreases as ψ increases.

There is a phenomenon called s. If there are a large number of these edges, defects such as dislocations and other defects are likely to occur on the surface of the grown layer, creating areas where normal growth cannot occur, which impairs the quality of the epitaxially grown layer. A rounded type that eliminates defects and produces high-quality epitaxial layers with few defects and high yield. The method includes a step of arranging dummy substrates in close contact with each other, and sequentially placing this growth substrate in close contact with a plurality of solutions on top of the 9 dummy substrates.

Although the present invention can be applied to any semiconductor material, here, an example of crystal growth of a double heterowafer made of InP/InGaAsP system, which has been attracting attention recently, will be explained in detail with reference to the drawings.

FIG. 4 is a cross-sectional view of a liquid phase epitaxial growth port used in a horizontal sliding liquid phase epitaxial growth method according to an embodiment of the present invention. First, the growth apparatus is installed in the positional relationship shown in Figure @4, and the growth solution 12 is stored in the solution reservoir l. The entire growth solution is designated 12, and each growth solution is designated 12 & 12b, 12c. The growth solutions 12a12b and 12c are each I
n, P mixed solution, In, G&As, P mixed solution, 1.
It is a P mixed solution. In the irradiation 6 of the substrate holding plate 4
A P growth substrate 11 is installed, and I! An InP dummy substrate lO is placed behind the IF growth substrate (in the direction opposite to the movement direction 8 of the growth substrate) so as to be stacked on this growth substrate.
Set up.

Next, the temperature is maintained at the set temperature, and then the substrate holding plate 4 is moved in the direction of arrow 8 to the position below the liquid reservoir 1QO, and the growth substrate is heated to a constant cooling temperature. 1
10 surface is brought into contact with the In, P mixed solution 12a.

! Figure 5 is a cross-sectional view showing the positional relationship between the growth solution 12 and the substrate 11 during epitaxial growth.0 As shown in this figure, not only the growth substrate but also the entire upper surface of the dummy substrate is in contact with the solution. ing. As a result, an epitaxial layer is grown.

Similarly, the growth substrate 11 is sequentially moved to the position of the solution reservoir 1, thereby forming vI epitaxial layers. In this practical example, there is an InP layer and an IaXG layer on the InP substrate.
The al-xAsl-yPy layer and the InP layer are epitaxially grown in sequence, and FIG. 7 shows the solution, growth substrate, and dummy substrate during epitaxial growth by the horizontal sliding liquid phase epitaxial growth method according to the second embodiment of the present invention. FIG. 3 is a cross-sectional view showing the positional relationship. As shown in FIG. 7, in this embodiment, a portion of the dummy substrate 1o is in contact with the solution 12. However, in the method shown in FIG. 7, the width of the dummy substrate 1o is set to be equal to the thickness of the partition wall between the adjacent solution reservoir.
Dummy substrate 1 is placed on growth substrate 11 during epitaxial growth.
Mixing of adjacent solutions as a medium must be prevented.

In the method of the present invention, when the substrate holding plate is moved, the mfIIVi brought in through the slight gap between the substrate holding plate 4 and the furnace boat 2 remains on the dummy substrate lo, and the mfIIVi is carried on the growth substrate 11. The solution you bring in will not be lost.

Therefore, unlike the conventional example, there is no deviation in the composition of the growth guiding liquid due to the introduction of the solution onto the growth substrate 11, and no deviation in the lattice constant or composition of the epitaxially grown layer occurs.

Furthermore, as shown in Fig. 6, epitaxial formation (A, A,, F, Engineering 1.A.-1pf/jfl19tdl*-a
#x. If it remains only in □, it becomes K. Therefore, failures during growth due to residual solution and decrease in yield, which occur in conventional epitaxial growth methods, are eliminated.

Further, in the method of the present invention, the edge gloss described in the explanation of the conventional example occurred on the dummy substrate 10 and disappeared on the growth substrate 11. As a result, a good epitaxial growth surface can be obtained without degrading the quality of the epitaxial growth layer due to edge gloss. This is particularly effective when performing epitaxial growth with a thickness of several μm or more, since the amount of edge gloss increases.

The dummy substrate used here may have any composition, but it is satisfactory as long as it has the same composition as the growth substrate.According to the epitaxial growth method of the present invention, the solution during growth is not transferred to other solution reservoirs. Changes in the composition of the solution due to carryover,
It is possible to prevent the abnormal table epitaxial growth that accompanies this, and furthermore, it is possible to prevent growth failures or decreases in yield9 due to the residual solution brought in during growth spreading and solidifying on the growth substrate after epitaxial growth. Moreover, a high quality epitaxial layer with few defects can be obtained.

In the embodiment, the epitaxial structure of an Ink/InGaAsP wafer has been explained as an example, but it goes without saying that the material may be any combination of semiconductor materials.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of an example of a conventionally used boat for liquid phase epitaxial growth. FIG. 2 is a cross-sectional view FA showing the relationship between the substrate and the solution during epitaxial growth using the boat shown in FIG. Figure 143 shows epitaxially grown surface gold produced by conventional methods. FIG. 4 shows the liquid phase epitaxial growth M+? used in one embodiment of the present invention. - FIG. Figure m5 is a cross-sectional view showing the relationship between the substrate and the solution during epitaxial growth using the boat of Figure 4. Figure 6 shows
FIG. 3 is an epitaxial growth surface diagram produced by an inventive method. FIG. 7 is a cross-sectional view showing the relationship between the substrate and the solution during epitaxial growth in the second practical array of the present invention. In each figure, 1. ta, ltb lc...
・・・・・．・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・
3--... Passageway, 4... Hitting/board holding plate, 5
・−・・・・Growth substrate, 6・・・・・・・Taste,
7,7a. yb, 7c ``''''''''Respectively, the entire solution, 1st scan, 2nd calculation, 3rd pot 1 solution, 8... Arrow 9 indicating the direction of movement/movement...・The remaining solidified solution,
1o...S-substrate for InP, 1l--Substrate for InP growth, 12.12a, 12b, 12c...
・・・・・・Respectively, the first In/P of the entire growth solution
Mixed solution, second In, G As, P mixed solution,
3rd I Tori P mixed solution. −),

Claims (1)

[Claims] In a liquid phase epitaxial growth method in which a crystal layer is grown on the growth substrate by applying a plurality of solution VCRs to the growth substrate, the growth substrate is used for growth in a direction opposite to the moving direction (front) of the growth substrate (C rearward). A liquid phase method characterized by comprising a step of: arranging a dummy substrate in close contact with the side surface (f, rear surface) of the substrate, and sequentially attaching the growth substrate to a plurality of solutions together with the dummy substrate disposed in close contact with each other. Epitaxial growth method.