JP2627901B2 - Crystal material melt susceptor lid - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention generally relates to an apparatus for producing a semiconductor single crystal,
In particular, it relates to a susceptor lid for improving the temperature environment of the dendrite web near the outlet of the melt receiver or the susceptor.

[Description of Related Art] The formation of ribbon-like crystals using the growth of dendrite web is not performed by a die for defining a shape,
Determined by crystallographic theory and surface tension. For indium antimonide, gallium arsenide, germanium, silicon and other ribbons of crystalline material, put needle-like seed crystals of crystalline material into the melt pool of crystalline material and supercool the seed crystal in the melt pool by 2-3 degrees , And the seed crystal is first grown laterally as the pool temperature decreases to form a button. Then, when the seed crystal is pulled up, the boundary between the secondary needle-like crystals on the two faces expands from each end of the button and extends into the pool. The frame that supports the liquid film of the molten material is formed by the buttons and the needle-shaped crystals, and the molten material is crystallized to form a web having a thickness of approximately 0.1 to 0.2 mm. Replenishing the melt pool as the needle crystal ribbons are withdrawn from the pool theoretically allows the web and boundary-forming needles to grow indefinitely. The ribbon width and growth rate are determined by the thermal conditions of the melt pool and the atmosphere near the growing needle crystal ribbon. If a more detailed description of the formation of dendrite webs is needed,
Journal of Crystal Growth
Grystal Growth, Vol. 50 (1980), pages 221-235, by RG Seidensticker (one of the present inventors) and RH Hopkins (RHHopkins). See the report entitled "Grow Silicon Ribbon with Dendrite Web."

SUMMARY OF THE INVENTION The gist of the present invention is a lid for a susceptor for melting a crystalline material, wherein the lid has an inner surface, an outer surface, and a substantially single-crystal dendrite web of the crystalline material. In the form of a plate with a central slot to be lifted, a pair of openings are located on the extension of the slot adjacent both ends of the slot, and a groove is provided between the slot and each opening. Extending and extending inward from the outer surface of the lid to a position adjacent to the inner surface, wherein the slot, the opening, and the groove cooperate with each other to control heat radiation from the dendrite web; A lid for producing a substantially uniform heat distribution in a transverse direction of said dendrite web adjacent an inner surface.

EXAMPLES In order that the present invention may be more clearly understood, preferred embodiments of the present invention will be described below with reference to the accompanying drawings, but the following examples are given for illustrative purposes.

In the accompanying drawings, in particular in FIG. 1, a susceptor 1 made of molybdenum or another material is shown, which is heated by an induction coil 3. At the center of the susceptor 1, there is a cavity 5, and a quartz crucible 7 is provided inside the cavity. A lid 9 formed from a molybdenum plate covers the crucible 7. The lid has a substantially flat outer surface 11 and an inner surface 13 with a centrally located slot 15 extending through the lid. An opening 17 is provided on the extension of the slot 15 and adjacent to each end of the slot, and the opening 17 has a generally round cross section. A groove 19 extends between the slot 15 and each opening. The groove 19 extends from the outer surface 11 to the inside of the lid 9, and a thin band portion 21 is left on the inner surface side of the groove 19.
A plurality of heat insulating sheets 23 and 25 are disposed adjacent to the outer surface of the lid 9, and each heat insulating sheet is provided with a slot 15 and an opening 17 of the lid 9.
It has slots 27 and 29 aligned with. Slot 27,
29 is wider and longer than slot 15 and opening 17,
The outer slot 29 is wider and longer than the inner slot 27.

A pool or melt of silicon or other crystalline material
A single crystal dendrite web 33 of silicon or other crystalline material is formed inside the crucible 7 and melts.
Increased from 31.

As shown in FIGS. 2 and 3, the dendrite web
The radiation heat loss from 33 is different for the case with the groove 19 and the case without the groove. The groove 19 provided in the susceptor lid 9 of this embodiment is shown in a view from the edge of the growing web 33, which is substantially the same as a view of the peripheral area from the center of the web 33. Are the same. Since the groove 19 does not penetrate completely through the lid 9 and thus leaves a strip 21, the heat loss from the melt 31 is controlled in much the same way as the lid 9 without the groove shown in FIG. . However, the dendrite web
In the portion slightly above the inner surface of the lid 9 of 33, the slot 15 is substantially larger than in the case shown in FIG. Second
In the case shown in the figure, heat radiation from the melt is blocked by the inner surface of the lid 9, and near the end of the slot 15, heat radiation from the web 33 is blocked by the vertical wall 35 of the slot 15. Thus, the heat loss over the entire width of the web is not uniform, and a heat distribution occurs within the web 33, represented by an isotherm that curves upwardly adjacent the edge. As a result, the thermal stress inside the web increases. On the other hand, when the groove 19 is provided as shown in FIG. 3, the heat radiation from the melt 31 is blocked by the strip portion 21 as in the case shown in FIG. The radiant heat loss near the edge of the web 33 in the area adjacent to it is relatively uniform over the width of the web due to the grooves 19. This results in a heat distribution represented by a generally flat isotherm over the entire width of the web 33, or a heat distribution represented by a slightly downwardly bent isotherm at both ends, and the thermal stress inside the web 33 is reduced. descend. Because the heat stress inside the web 33 is reduced,
The web 33 is not deformed, and a crystal growth is performed that can produce a thinner and wider web and can increase the pulling rate to substantially increase the allowable growth rate of the web 33.

FIGS. 4, 5 and 6 show a slot in the form of a dog bone (the shape of a dog holding a bone), with circular openings 35 at both ends and enlarged at both ends. Slot 15a and opening 1
As shown by reference numerals 45 and 47, each of the ends 7 has a counterbore that is approximately half the thickness of the lid 9. Counterbore 45 and 47
Are perforated from the inner surface 11 of the lid 9. A replenishing port 49 adjacent to at least one side of the lid 9 to add silicon or other crystalline material to the melt pool 31 to make the process a continuous process.
Is provided. The width of the groove 19 is substantially the same as the width of the slot 15a. Fig. 7 shows the slot 15 and the counterbore
45, an opening 17 and a counterbore 47, a groove 19 and a strip 21 are shown. The slot 15, the opening 17 and the groove 19 are united to form a single enlarged slot, and a band-like portion 21 seals the inside of the lid inside both ends of the enlarged slot-like opening.

[Operation and Effect] The heat radiated from the web 33 adjacent to the inner surface 13 of the lid 9 is controlled by the cooperative action of the slots 15 and 15a, the opening 17 and the groove 19, and the web adjacent to the inner surface 13 of the lid 9 is controlled. The isotherm inside the 33 becomes almost flat, so that the internal stress of the web 33 is reduced, the deformation during crystal growth is reduced, it is possible to increase the pulling speed and produce a wide web, The allowable growth rate of dendrite web is greatly increased.

[Brief description of the drawings]

FIG. 1 is a partial perspective view showing a lid of a susceptor used to form a silicon melt pool for pulling up a substantially single crystal dendrite web. FIG. 2 and FIG. 3 are explanatory diagrams showing heat radiation loss from the pool and the dendrite web. FIG. 4 is a plan view of a susceptor lid according to the present invention. FIG. 5 is a sectional view taken along the line III-III of FIG. FIG. 6 is a partial perspective view of the opening and groove of the slot shown in FIGS. 1 and 2. FIG. 7 is a partial perspective view of a modified embodiment. 1 susceptor 9 lid 15 slot 17 opening 19 groove 31 melt pool 33 dendrite web

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Paul Anthony Piotroski Monroville Northern Pike, Pennsylvania, United States of America 4607 (72) Inventor Raymond George Seidensticker Pittsburgh Castle, Pennsylvania, United States of America Gate Road 319 (56) References JP-A-61-174188 (JP, A)

Claims (4)

(57) [Claims] 1. A susceptor lid for melting a crystalline material, said lid being in the form of a plate having an inner surface, an outer surface, and a central slot for lifting a substantially single crystal dendrite web of said crystalline material. And a pair of openings,
A slot extending between the slot and each of the openings and extending inward from the outer surface of the lid to a position adjacent to the inner surface, the groove extending between the slot and each opening adjacent to both ends of the slot; The slot, the opening, and the groove cooperate with each other to control heat radiation from the dendrite web to produce a substantially uniform heat distribution in a transverse direction of the dendrite web adjacent the inner surface of the lid. A lid characterized in that the lid is adapted to be made. 2. The lid of claim 1 wherein each end of the slot has an enlarged portion and the slot is generally dog bone shaped. 3. The lid according to claim 2, wherein the enlarged portion is substantially circular. 4. The lid according to claim 1, wherein the slot and the opening are edged from the outer surface.