Sumitomo Mitsubishi Silicon Corporation

Sumitomo Metal Industries, Inc.

Eiichi Asayama

Toshiaki Ono

Tadami Tanaka

Masataka Horai

Shigeru Umeno

Hideshi Nishikawa

Yasuo Koike

Masataka Hourai

Hiroki Murakami

Takayuki Kubo

Shinsuke Sadamitsu

Kouji Sueoka

Hisashi Katahama

A method for growing a silicon single crystal used for semiconductor integrated circuit devices, wherein the single crystal is grown by the CZ method at a nitrogen concentration of 1&#xd7;10atoms/cm&#x2013;1&#xd7;10atoms/cmwith a cooling rate of not less than 2.5&#xb0; C./min at a crystal temperature of 1150&#xb0; C.&#x2013;1000&#xb0; C., in which case, the pulling rate is adjusted such that the outside diameter of a circular region including oxidation-induced stacking faults generated at the center of a wafer which is subjected to the oxidation heat treatment at high temperature is not more than &#x2157; of the wafer diameter, wherein the wafer is prepared by slicing the grown single crystal. In the growth method, the concentration of oxygen in the silicon single crystal is preferably not more than 9&#xd7;10atoms/cm(ASTM '79). With this method, the silicon single crystal, in which the generation of Grown-in defects can be effectively suppressed, can be produced in a simple process without any increase in the production cost. Moreover, a specification of the oxygen concentration and the application of the outward diffusion treatment are capable of producing a wafer, which is optimally used for monitoring particles.

Method for growing silicon single crystal

There are provided silicon single crystal, silicon wafer, and epitaxial wafer having a sufficient gettering effect suitable for a large-scale integrated device. The silicon single crystal which is suitable for an epitaxial wafer is grown with nitrogen doping at a concentration of 1&#xd7;10atoms/cmor more, or with nitrogen doping at a concentration of 1&#xd7;10atoms/cmand carbon doping at a concentration of 0.1&#xd7;10-5&#xd7;10atoms/cmand/or boron doping at a concentration of 1&#xd7;10atoms/cmor more. The silicon wafer is produced by slicing from the silicon single crystal, and an epitaxial layer is grown on a surface of the silicon wafer to produce the epitaxial wafer. The present invention provides an epitaxial wafer for a large-scale integrated device having no defects in a device-active region and having an excellent gettering effect without performance of an extrinsic or intrinsic gettering treatment, which is a factor for increasing the number of production steps and production costs.

Silicon single crystal, silicon wafer, and epitaxial wafer

Epitaxial wafers showing marked IG effects can be manufactured from silicon single crystals doped or not doped with nitrogen without requiring any additional heat treatment process step while reducing the density of epitaxial layer defects. According to the first manufacturing method, an epitaxial layer is allowed to grow on the surface of a wafer sliced from a single crystal produced by employing a cooling rate of not less than 7.3&deg; C./min in the temperature range of 1200-1050&deg; C. in the step of pulling up thereof. According to the second manufacturing method, an epitaxial layer is allowed to grow on the surface of a silicon wafer sliced from a silicon single crystal doped with 1&times;10 atoms/cm to 1&times;10 atoms/cm as produced by employing a cooling rate of not less than 2.7&deg; C./min in the temperature range of 1150-1020&deg; C. and then a cooling rate of not more than 1.2&deg; C./min in the temperature range of 1000-850&deg; C. in the step of pulling up thereof.

Method of manufacturing epitaxial wafer and method of producing single crystal as material therefor

The invention relates to a method of producing epitaxial wafers for the manufacture of high integration density devices capable of showing stable gettering effect. Specifically, it provides (1) a method of producing epitaxial wafers which comprises subjecting a silicon wafer sliced from a single crystal ingot grown by doping with not less than 1&times;10 atoms/cm of nitrogen to 15 minutes to 4 hours of heat treatment at a temperature not lower than 700&deg; C. but lower than 900&deg; C. and then to epitaxial growth treatment. It is desirable that the above single crystal ingot have an oxygen concentration of not less than 11&times;10 atoms/cm . Further, (2) the above heat treatment is desirably carried out prior to the step of mirror polishing of silicon wafers. Furthermore, (3) it is desirable that the pulling rate be not increased in starting tail formation as compared with the pulling rate of the body in growing the above single crystal ingot. By taking these means, it is possible to produce epitaxial wafers having an almost constant, high level of gettering effect irrespective of the site of wafer slicing from the single crystal ingot and, furthermore, suppress the occurrence of defects within the epitaxial layer.

Method of producing epitaxial wafers

There are provided silicon single crystal, silicon wafer, and epitaxial wafer having a sufficient gettering effect suitable for a large-scale integrated device. The silicon single crystal which is suitable for an epitaxial wafer is grown with nitrogen doping at a concentration of 1&times;10 atoms/cm or more, or with nitrogen doping at a concentration of 1&times;10 atoms/cm and carbon doping at a concentration of 0.1&times;10 &minus;5&times;10 atoms/cm and/or boron doping at a concentration of 1&times;10 atoms/cm or more. The silicon wafer is produced by slicing from the silicon single crystal, and an epitaxial layer is grown on a surface of the silicon wafer to produce the epitaxial wafer. The present invention provides an epitaxial wafer for a large-scale integrated device having no defects in a device-active region and having an excellent gettering effect without performance of an extrinsic or intrinsic gettering treatment.

Silicon single crystal, silicon wafer, and epitaxial wafer.

A method of producing high-quality epitaxial wafers with scarce occurrence of epitaxial layer defects by allowing an epitaxial layer on wafers sliced from a nitrogen-doped silicon single crystal as well as a method of pulling up a silicon single crystal to serve as the raw material therefore is provided. More particularly, a method of pulling up a single crystal from a nitrogen-doped silicon material melt while allowing the single crystal to grow is provided which comprises employing a passing or residence time in the temperature range of 1150-1050&deg; C. of not less than 50 minutes and/or a passing or residence time in the temperature range of 1050-950&deg; C. of not more than 40 minutes in the step of pulling up of the single crystal. Further, a method of manufacturing epitaxial wafers is provided which comprises allowing an epitaxial layer on the surface of silicon wafers sliced from the single crystal pulled up by the method mentioned above.

Method of pulling up silicon single crystal and method of manufacturing epitaxial wafer

Methods are designed to manufacture an epitaxial wafer wherein the formation of defects in an epitaxial layer is sufficiently suppressed even if the epitaxial wafer is prepared from a silicon single crystal which is grown while doped with nitrogen. Specifically, the methods are to grow an epitaxial layer on a wafer sliced from (1) a silicon single crystal wherein the oxygen concentration at an OSF ring region is 9&times;10 atoms/cm or less, (2) a silicon single crystal wherein the inside diameter of an OSF ring region is located at a position which is 85% or more of the wafer diameter, and (3) a silicon single crystal doped with nitrogen at a concentration between 1&times;10 atoms/cm or more and 1&times;10 atoms/cm or less. Further, another method is to grow an epitaxial layer on (4) a wafer sliced from a silicon single crystal doped with nitrogen at a concentration between 1&times;10 atoms/cm or more and less than 1&times;10 atoms/cm , the epitaxial layer being grown after the sliced wafer has been heat-treated at a temperature between 1200&deg; C. and 1300&deg; C. for 1 minute or more. According to the above methods, the density of defects in an epitaxial layer can be reduced to 0.1 piece/cm or less.

Growing community of inventors

Saga, Japan

Eiichi Asayama