Sumitomo Mitsubishi Silicon Corporation

Sumco Corporation

Japan Super Quartz Corporation

Nobumitsu Takase

Shinsuke Sadamitsu

Tsuyoshi Nakamura

Ken Hamada

Shuichi Inami

Hideshi Nishikawa

Makoto Ito

Koji Sueoka

Yasuhiro Kogure

Hideki Watanabe

Keiichi Takanashi

Masataka Hourai

Masanori Fukui

Hiroki Murakami

Hiroshi Hayakawa

Takayuki Kihara

Kazuyuki Egashira

Masataka Horai

Hiroyuki Takao

Koujl Sueoka

Kouji Sueoka

Leakage of silicon melt is monitored and touch of a seed crystal at the silicon melt is detected, and in addition, reinforcement of a vitreous silica crucible to be endurable during pulling for a long time and decrease of impurity concentration of a silicon single crystal can be expected. A method for manufacturing a silicon single crystal is provided. The method includes: detecting touching status of a seed crystal at silicon melt by supplying voltage Vusing a crucible side as a negative electrode and a wire side as a positive electrode and by monitoring change of the voltage, when the seed crystal provided at a front end of the wire touches the silicon melt inside a vitreous silica crucible; devitrifying an inner surface of the vitreous silica crucible as supplying voltage Vusing the crucible side as a positive electrode and the wire side as a negative electrode during a temperature control period; and growing a silicon single crystal by slowly pulling the seed crystal as supplying voltage Vusing the crucible side as a negative electrode and the wire side as a positive electrode after the temperature control period.

Method of manufacturing silicon single crystal, apparatus for pulling silicon single crystal and vitreous silica crucible

In a method for growing a silicon single crystal, a silicon single crystal is grown by the Czochralski method to have an oxygen concentration of 12&#xd7;10to 18&#xd7;10atoms/cmon ASTM-F121 1979. A mixed gas of an inert gas and a gaseous substance containing hydrogen atoms is used as an atmospheric gas for growing the single crystal. A temperature of the silicon single crystal is controlled during the growth of the crystal such that the ratio Gc/Ge of an axial thermal gradient Gc at the central portion of the crystal between its melting point and its temperature of 1350&#xb0; C. to an axial thermal gradient Ge at the periphery of the crystal between its melting point and its temperature of 1350&#xb0; C. is 1.1 to 1.4. The axial thermal gradient Gc at the central portion of the crystal is 3.0 to 3.5&#xb0; C./mm.

Method for growing silicon single crystal and method for manufacturing silicon wafer

A silicon single crystal is grown using the Czochralski method. During the crystal growth, a thermal stress is applied to at least a portion of the silicon single crystal. A gaseous substance containing hydrogen atoms is used as an atmospheric gas for growing the crystal.

Method for growing silicon single crystal

This method for producing silicon single crystals includes: growing a silicon single crystal by the Czochralski method while cooling at least part of the silicon single crystal under growth with a cooling member which circumferentially surrounds the silicon single crystal and has an inner contour that is coaxial with a pull axis, wherein an ambient gas in which the silicon single crystal is grown includes a hydrogen-atom-containing substance in gaseous form. This silicon single crystal is produced by the above method.

Method for producing silicon single crystals and silicon single crystal produced thereby

A high-resistance silicon wafer is manufactured in which a gettering ability, mechanical strength, and economical efficiency are excellent and an oxygen thermal donor is effectively prevented from being generated in a heat treatment for forming a circuit, which is implemented on the side of a device maker. A heat treatment for forming an oxygen precipitate nucleus is performed at 500 to 900&#xb0; C. for 5 hours or more in a non-oxidizing atmosphere and a heat treatment for growing an oxygen precipitate is performed at 950 to 1050&#xb0; C. for 10 hours or more on a high-oxygen and carbon-doped high-resistance silicon wafer in which resistivity is 100 &#x3a9;cm or more, an oxygen concentration is 14&#xd7;10atoms/cm(ASTM F-121, 1979) or more and a carbon concentration is 0.5&#xd7;10atoms/cmor more. By these heat treatments, a remaining oxygen concentration in the wafer is controlled to be 12&#xd7;10atoms/cm(ASTM F-121, 1979) or less. Thus, there is provided a high-resistance, low-oxygen and high-strength silicon wafer in which resistivity is 100 &#x3a9;cm or more and an oxygen precipitate (BMD) having a size of 0.2 &#x3bc;m is formed so as to have high density of 1&#xd7;10/cmor more.

High resistance silicon wafer and its manufacturing method

A high-resistance silicon wafer is manufactured, in which a gettering ability and economical efficiency is excellent and an oxygen thermal donor is effectively prevented from being generated in a heat treatment for forming a circuit, which is to be implemented on the side of a device manufacturer. In order to implement the above, a high-temperature heat treatment at 1100&#xb0; C. or higher is performed on a carbon doped high-resistance and high-oxygen silicon wafer in which specific resistivity is 100 &#x3a9;cm or more and a carbon concentration is 5&#xd7;10to 5&#xd7;10atoms/cmso that a remaining oxygen concentration becomes 6.5&#xd7;10atoms/cmor more (Old-ASTM). As this high-temperature treatment, an OD treatment for forming a DZ layer on a wafer surface, a high-temperature annealing treatment for eliminating a COP on the surface layer, a high-temperature heat treatment for forming a BOX layer in a SIMOX wafer manufacturing process and the like can be used.

High-resistance silicon wafer and process for producing the same

A silicon annealed wafer having a sufficient thick layer free from COP defects on the surface, and a sufficient uniform BMD density in the inside can be produced by annealing either a base material wafer having nitrogen at a concentration of less than 1&#xd7;10atoms/cm, COP defects having a size of 0.1 &#x3bc;m or less in the highest frequency of occurrence and no COP defects having a size of 0.2 &#x3bc;m or more, oxygen precipitates at a density of 1&#xd7;10counts/cmor more, and BMDs (oxygen precipitates), where the ratio of the maximum to the minimum of the BMD density in the radial direction of the wafer is 3 or less, or a base material wafer grown at specific average temperature gradients within specific temperature ranges and specific cooling times for a single crystal at a nitrogen concentration of less than 1&#xd7;10atoms/cm, employing the Czochralski method. Moreover, a silicon epitaxial wafer having very small defects and a uniform BMD distribution in the inside can be formed by growing an epitaxial layer on the surface of either the first type base material wafer or the second type base material wafer. Both the silicon annealed wafer and the silicon epitaxial wafer greatly reduce the rate of producing defective devices, thereby enabling the device productivity to be enhanced.

Silicon annealed wafer and silicon epitaxial wafer

A high resistivity p type silicon wafer with a resistivity of 100 &#x3a9;cm or more, in the vicinity of the surface being formed denuded zone, wherein when a heat treatment in the device fabrication process is performed, a p/n type conversion layer due to thermal donor generation is located at a depth to be brought into contact with neither any device active region nor depletion layer region formed in contact therewith or at a depth more than 8 &#x3bc;m from the surface, and a method for fabricating the same. The high resistivity silicon wafer can cause the influence of thermal donors to disappear without reducing the soluble oxygen concentration in the wafer, whereby even if various heat treatments are performed in the device fabrication process, devices such as CMOS that offer superior characteristics can be fabricated. The wafer has wide application as a substrate for a high-frequency integrated circuit device.

High resistivity silicon wafer and method for fabricating the same

To suppress a fluctuation in resistivity around a target value to thereby stably manufacture high resistivity silicon single crystals having almost the same resistivity values in a manufacturing method wherein a silicon raw material is molten to manufacture a high resistivity silicon single crystal in the range of from 100 to 2000 &#x3a9; cm with a CZ method. In a case where poly-silicon produced with a Siemens method using trichlorosilane as raw material is used as the silicon raw material, an impurity concentration in the silicon raw material is selected so as to be controlled in the range of from &#x2212;5 to 50 ppta method in terms of (a donor concentration&#x2014;an acceptor concentration) and the selected poly-silicon is used. In a case of a MCZ method, the poly-silicon is selected in the range of from &#x2212;25 to 20 ppta and the selected poly-silicon is used. Instead of the raw material, poly-silicon produced with a Siemens method using monosilane as raw material is used. Alternatively, a silicon crystal manufactured with a CZ method or a MCZ method using poly-silicon raw material is used.

Manufacturing method of high resistivity silicon single crystal

In a device and a method for measuring the position of the liquid surface of a melt while a single crystal is being pulled, two measuring-lines are defined in an image of a fusion ring which is captured by means of a two-dimensional CCD camera, the intersections of the respective measuring lines and the fusion ring, on the opposite sides of the fusion ring, are detected, and the central position of the single crystal is calculated based on the intervals between the intersections on the opposite sides of the fusion ring, whereby the position of the liquid surface of the melt is determined.

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Tokyo, Japan

Nobumitsu Takase