SEMICONDUCTOR CRYSTAL GROWTH USING SOURCE POWDER FROM CRUCIBLE WALL
A crucible for manufacturing semiconductor crystals may be disposed adjacent to a heating element. The crucible may include a first seed crystal site and a second seed crystal site at opposed ends of the crucible. A compartment may be defined between an outer wall and an inner wall of the crucible, where the inner wall is formed with a porous graphite membrane. Source powder loaded into the compartment may then be heated by the heating element to sublimate and diffuse from the compartment and through the inner wall to provide crystal growth of a first seed crystal at the first seed crystal site and of a second seed crystal at the second seed crystal site.
1 . A crucible for manufacturing a semiconductor crystal, comprising:
an outer wall;
an inner wall formed using a graphite membrane and defining a compartment between the inner wall and the outer wall, the graphite membrane having a porosity sufficient to enable diffusion of vapor sublimated from source powder disposed within the compartment when the source powder is sublimated by a heating element;
a first seed crystal site disposed to receive a first seed crystal; and
a second seed crystal site at an opposed end of the crucible from the first seed crystal site and disposed to receive a second seed crystal.
2 . The crucible of claim 1 , comprising:
a graphite filter within the crucible and positioned above the second seed crystal site when the crucible has a vertical orientation and the second seed crystal site is at a bottom of the crucible.
3 . The crucible of claim 1 , comprising:
a divider configured to separate the crucible into a first crucible portion and a second crucible portion.
4 . The crucible of claim 13 , wherein the divider includes a graphite membrane having a porosity that does not permit passage of the vapor between the first crucible portion and the second crucible portion.
5 . The crucible of claim 13 , wherein the crucible is detachable at the divider into a first crucible portion including the first seed crystal site and a second crucible portion including the second seed crystal site.
6 . The crucible of claim 1 , wherein the crucible is cylindrical.
7 . A semiconductor manufacturing assembly, comprising
a heating element; and
a crucible disposed adjacent to the heating element and including a first seed crystal site and a second seed crystal site at opposed ends of the crucible, the crucible including an outer wall, the crucible further including an inner wall formed with a porous graphite membrane, wherein a compartment defined between the outer wall and the inner wall is disposed to receive source powder, which, when heated by the heating element, sublimates and diffuses from the compartment and through the inner wall to provide crystal growth of a first seed crystal at the first seed crystal site and of a second seed crystal at the second seed crystal site.
8 . The semiconductor manufacturing assembly of claim 1 , wherein the heating element includes a radio frequency (RF) coil, and the crucible is disposed within the RF coil.
9 . The semiconductor manufacturing assembly of claim 1 , wherein the crucible is disposed vertically within the heating element.
10 . The semiconductor manufacturing assembly of claim 3 , wherein the second seed crystal site is positioned at a bottom of the crucible, and comprising:
a graphite filter positioned above the second seed crystal.
11 . The semiconductor manufacturing assembly of claim 1 , wherein the crucible is disposed horizontally within the heating element.
12 . The semiconductor manufacturing assembly of claim 1 , comprising:
a divider configured to separate the crucible into a first crucible portion and a second crucible portion.
13 . The semiconductor manufacturing assembly of claim 6 , wherein the divider includes a graphite membrane having a porosity that does not permit passage of the vapor between the first crucible portion and the second crucible portion.
14 . The semiconductor manufacturing assembly of claim 6 , wherein the crucible is detachable at the divider into a first crucible portion including the first seed crystal site and a second crucible portion including the second seed crystal site.
15 . The semiconductor manufacturing assembly of claim 1 , wherein the crucible is cylindrical.
16 . The semiconductor manufacturing assembly of claim 1 , comprising:
a support member positioned to support the crucible and configured to move the crucible relative to the heating element, to thereby control a temperature gradient within the crucible that occurs in response to heating provided by the heating element.
17 . A method of making semiconductor crystals, comprising:
loading source powder into a compartment formed between an outer wall and an inner wall of a crucible, the inner wall being formed using a graphite membrane;
heating the source powder with a heating element to sublimate the source powder and thereby cause diffusion of the sublimated source powder through the inner wall and into at least one chamber of the crucible within the inner wall; and
monitoring crystal growth within the chamber of a first crystal from a first seed crystal positioned at a first seed crystal site and of a second crystal from a second seed crystal positioned at a second seed crystal site at an opposed end of the crucible from the first seed crystal site.
18 . The method of claim 17 , further comprising:
detaching a first crucible portion including the first seed crystal site from a second crucible portion including the second seed crystal site; and
loading additional source powder within a portion of the compartment included in the second crucible portion.
19 . The method of claim 17 , further comprising:
moving the crucible and/or the heating element relative to one another to control a temperature gradient within the crucible.
20 . The method of claim 17 , further comprising:
adjusting a temperature gradient within the crucible to re-sublimate the second crystal and enable continued growth of the first crystal.