US 8,961,686 B2Granted

Method of manufacturing monocrystal, flow straightening cylinder, and monocrystal pulling-up device

AssigneeSumco Techxiv Corporation

InventorsShinichi Kawazoe, Fukuo Ogawa, Yasuhito Narushima, Toshimichi Kubota

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Abstract

For manufacturing a monocrystal, a monocrystal pulling-up device controls pressure within a flow straightening cylinder to be from 33331 Pa to 79993 Pa and a flow velocity of inert gas in the cylinder to be from 0.06 m/sec to 0.31 m/sec (0.005 to 0.056 SL/min·cm2) during a post-addition-pre-growth period. By controlling the flow velocity of the inert gas to be in the above-described range during the post-addition-pre-growth period, the inert gas flows smoothly even when the pressure within the cylinder is relatively high. Evaporation of a volatile dopant because of a reverse flow of the inert gas can be restrained. The volatile dopant can be prevented from adhering to the flow straightening cylinder in an amorphous state, and the volatile dopant can be prevented from dropping into a melt or sticking on the melt while growing a crystal. Foulings can be easily removed.

Claims6

Dependent claims

A method of manufacturing a monocrystal, comprising:

providing a monocrystal pulling-up device comprising:
(i) a chamber,
(ii) an intake provided on an upper portion of the chamber for introducing an inert gas into the chamber,
(iii) a crucible disposed within the chamber for accommodating a dopant-added melt prepared by adding a volatile dopant to a silicon melt,
(iv) a flow straightening cylinder extending from the intake of the chamber to a vicinity of a surface of the dopant-added melt for guiding the inert gas to the dopant-added melt, the flow straightening cylinder comprising a first cylinder connected to the intake and having a maximum inner diameter of a first diameter and a second cylinder connected to an end of the first cylinder near the surface of the dopant-added melt and having a maximum inner diameter of a second diameter which is smaller than the first diameter, and
(v) a pulling-up portion for pulling-up a seed crystal after the seed crystal is brought into contact with the dopant-added melt so as to pass through the flow straightening cylinder;
and
controlling a flow velocity of an inert gas in an upper portion of the chamber above the flow-straightening cylinder in a range of less than 0.06 m/sec (0.005 SL/min·cm2), and controlling a pressure in the flow straightening cylinder to be in a range of 33331 Pa (250 Torr) to 79993 Pa (600 Torr) and a flow velocity of the inert gas in the flow straightening cylinder to be in a range of 0.06 m/sec to 0.31 m/sec (0.005 to 0.056 SL/min·cm2) during a period from the addition of the volatile dopant to the silicon melt accommodated in the crucible until a crystal body of the monocrystal enters into the flow straightening cylinder by being pulled-up using the pulling-up portion.

5 more elements

A flow straightening cylinder provided in a monocrystal pulling-up device including:

(i) a chamber;
(ii) an intake provided on an upper portion of the chamber for introducing an inert gas into the chamber;
and
(iii) a crucible disposed within the chamber for accommodating a dopant-added melt, prepared by adding a volatile dopant to a silicon melt, wherein the flow straightening cylinder is shaped as a cylinder extending from the intake of the chamber to a vicinity of a surface of the dopant-added melt for guiding the inert gas to the dopant-added melt, while allowing the monocrystal to be pulled-up to pass through the cylinder, and wherein the flow straightening cylinder comprises:
a first cylinder which is connected to the intake and which is substantially shaped as a cylinder whose largest inner diameter is a first diameter;
and
a second cylinder which is connected to an end of the first cylinder near the surface of the dopant-added melt and which is substantially shaped as a cylinder whose largest inner diameter is a second diameter smaller than the first diameter.

4 more elements

Dependencies are inferred from the claim text.

Facts

Application: 12/678,400Filed 25 Jul 2008
Published: US 2010/0212580 A126 Aug 2010
Granted: 24 Feb 2015
Term ends: Not estimatedThe source records don’t support an estimate.

Classification7 codes

C30B 15/04
Adding crystallising materials or reactants forming it in situ to the melt: adding doping materials, e.g. for n-p-junction
C30B 15/20
Single-crystal growth by pulling from a melt, e.g. Czochralski method: controlling or regulating
C30B 29/06
Elements: silicon
Y10T 117/1064
Seed pulling: including a fully-sealed or vacuum-maintained crystallization chamber [e.g., ampoule]