Shin-etsu Handotai Co., Ltd.

Shin-etsu Handotai Kabushiki Kaisha

Shin-etsu Handotai, Ltd.

Masatake Katayama

Hitoshi Habuka

Yutaka Ohta

Kiyoshi Mitani

Masanori Mayuzumi

Naoto Tate

Takao Abe

Konomu Ohki

Masatake Nakano

Kazushi Nakazawa

Isao Moroga

Norihiro Kobayashi

Hiroji Aga

Masaru Shinomiya

Yasuaki Nakazato

Satoshi Oka

Toru Otsuka

Hitoshi Tsunoda

Yuichi Matsumoto

Katsuo Yoshizawa

Akio Kanai

Shoichi Fujiya

Makoto Sato

Mitsuru Sugita

Akio Kasahara

Youichi Kumaki

Isao Shirai

Tsutomu Sato

Kazuo Mamada

A method of performing chemical vapor deposition which produces semiconductor crystalline thin films having small transition widths. The method involves the use of a cold-wall type reaction chamber that is equipped with a gas inlet at one end and a gas outlet at the other end and a semiconductor substrate support which supports a semiconductor substrate so that a main surface thereof is horizontal. A reactant gas is caused to flow horizontally through the reaction chamber to effect the growing of a crystalline thin film on the main surface of the semiconductor substrate. The semiconductor substrate is arranged within the reactor chamber within a distance W which is measured from a leading edge of the semiconductor substrate at a most upstream position along a direction toward the gas outlet where W indicates an internal width of the reaction chamber. The semiconductor substrate is also in a location having a W/G ratio of 15 or greater, where G represents a distance between the main surface of the semiconductor substrate and a ceiling of the reaction chamber.

Method of chemical vapor deposition

In a method and an appratus for a thin film growth on a semiconductor crystal substrate, impurities and contaminants absorbed on the inside wall of the reaction vessel are very harmful because these impurities and contaminants will deteriorate the quality of the thin film. A method and an apparatus by which the quantity of these impurities and contaminants absorbed on the inside wall of the reaction vessel can be restrained and removed easily are disclosed in this invention, wherein a semiconductor crystal substrate is mounted in the reaction vessel, and the wall of the reation vessel is cooled forcibly by a coolant while the substrate is under heating procedure to grow a thin film on the substrate by supplying the raw material gas into the reaction vessel. And the temperature of the wall of the reaction vessel during the procedure except the thin film growth is kept higher temperature than the temprature of the wall of the reaction vessel during the thin film growth procedure.

Method and apparatus for thin film growth

A method for microscopically smoothing a surface of a wafer made of silicon single crystal having a low resistivity. In the method, a native oxide film grown on a surface of a wafer having polished by an ordinary mirror polishing process is removed at a temperature of less than 100.degree. C. with use of a mixture gas of HF and H.sub.2, and then an organic substance deposited thereon is removed at a temperature of less than 800.degree. C. with use of a mixture gas of HCl and H.sub.2. Re-growth of an oxide film is suppressed in a consistent H.sub.2 atmosphere, during which the wafer is substantially not varied in its surface roughness. Then the wafer is thermally treated in an H.sub.2 gas atmosphere at a temperature of not less than 800.degree. C. and less than 1000.degree. C. A process of etching the silicon single crystal substrate and a process of depositing silicon atoms caused by decomposition of a silane compound generated are competitively carried out to thereby soften the microscopic rough surface of the wafer and to improve a smoothness over the smoothness of the mirror-polished surface. Since all process temperatures are set to be less than 1000.degree. C., vaporization of impurities in the wafer can be suppressed and its low resistivity can be secured.

Method for smoothing surface of silicon single crystal substrate

Proposed is an improvement in the process for the preparation of an SOI wafer comprising the steps of: forming an oxidized surface film on the mirror-polished surface of a first mirror-polished semiconductor silicon wafer as the base wafer; forming a doped layer with a dopant in a high concentration on the mirror-polished surface of a second mirror-polished semiconductor silicon wafer as the bond wafer; bringing the base wafer and the bond wafer into contact each with the other at the oxidized surface film and the doped layer; and subjecting the thus contacted semiconductor silicon wafers to a heat treatment to effect integral bonding thereof into a precursor of an SOI wafer. The improvement of the invention is accomplished by polishing the surface of the doped layer on the bond wafer before the base wafer and the bond wafer are joined by contacting at the oxidized surface film and the doped layer so that a great improvement can be obtained in the bonding strength between layers.

SOI wafer and method for the preparation thereof

In the formation of a thin film on the surface of a semiconductor crystal substrate by using a horizontal type vapor phase growth apparatus, the distribution of the thickness and resistivity of the thin film can be properly obtained by adjusting the concentration distribution of the raw material gas in the mixture gas in the width direction of the reaction vessel over the substrate surface. And in the reaction vessel, carrier gas is supplied from the position close to the transfer port of the substrate, and raw material gas is supplied from the position located in the downstream side of a vortex generation region caused by the flow of the carrier gas.

Method for vapor phase growth

A method of fabricating a bonded wafer which is capable of reducing the concentrations of impurities, and more particularly the boron concentration, at the interface of bonding in the bonded wafer, wherein first and second wafers to be bonded are finish-cleaned, then the wafers are temporarily stored in a closed box so as to isolate the wafers from clean-room air, thereafter the first and second wafers are superposed in a clean atmosphere which is held out of direct contact with clean-room air, and finally the superposed first and second wafers are bonded together by a heat-treatment.

Method of fabricating bonded wafer

A silicon nitride layer 12b is thermally grown on the topmost surface of the heat treatment jig 12 composed of silicon or silicon carbide in a nitrogen ambience. The silicon nitride layer 12b is thermally grown in a nitrogen ambience in the temperature range of 1,100.degree. C.-1,300.degree. C. It is desirable to remove slightly the surface of the jig by, for example, hydrogen etching before thermally growing the silicon nitride layer 12b. After the etching, a silicon oxide layer can be thermally grown on the jig surface in an oxygen ambience before thermally growing the silicon nitride layer 12b.

Heat treatment jig for semiconductor wafers and a method for treating a

A reactor for chemical vapor deposition which is capable of producing semiconductor crystalline thin films having small transition widths. The reactor includes a cold-wall type reaction chamber that is equipped with a gas inlet at one end and a gas outlet at the other end and a semiconductor substrate support which supports a semiconductor substrate so that a main surface thereof is horizontal. A reactant gas is caused to flow horizontally through the reaction chamber to effect the growing of a crystalline thin film on the main surface of the semiconductor substrate. The semiconductor substrate is arranged within the reactor chamber within a distance W which is measured from a leading edge of the semiconductor substrate at a most upstream position along a direction toward the gas outlet where W indicates an internal width of the reaction chamber. The semiconductor substrate is also in a location having a W/G ratio of 15 or greater, where G represents a distance between the main surface of the semiconductor substrate and a ceiling of the reaction chamber.

Method of chemical vapor deposition and reactor therefor

A method for vapor-phase growth which allows an epiwafer of a smooth surface free from microroughness to be produced is provided. This method comprises a step of heating up a silicon single crystal substrate in an ambience of an inert gas started at a temperature of less than 800.degree. C. and a step of removing a native oxide film formed on the surface of the silicon single crystal substrate by etching with hydrogen gas in an ambience of hydrogen gas at a temperature of not less than 950.degree. C. and not more than 1190.degree. C. prior to the vapor-phase growth.

Method for vapor-phase growth

A method for producing a semiconductor substrate in which no autodoping occurs and slip dislocations in the substrate are reduced. The method involves forming a silicon nitride film on the backside of an n.sup.- -silicon substrate, epitaxially growing an n.sup.+ -buffer layer and a p.sup.+ -layer on the front side of the n.sup.- -silicon substrate, and decreasing the thickness of the n.sup.- -silicon substrate from the backside.

Method for producing semiconductor substrate

SOI (silicon-on-insulator) substrates are efficiently produced by a method which comprises superposing and bonding at least three single crystal silicon wafers through the medium of a SiO.sub.2 film formed on the surface of each of the wafers and cutting the bonded wafers along planes perpendicular to the direction of superposition thereof. The cutting can be infallibly attained with high dimensional accuracy without entailing such adverse phenomena as the vibration of the blade of a cutting tool by providing at the portions destined to be cut the grooves for guiding the blade of the cutting tool in advance of the cutting work.

Method for production of SOI substrate

A method of estimating the amount of boron on the surface of silicone samples in which a plurality of reference samples shallowly ion-implanted with boron in different dosages are prepared and heat-treated under the same conditions of temperature and time as are used in a bonding heat treatment to obtain the bonded wafer, thereafter, the boron profile in the direction of the depth of the bonding interface in each reference sample is measured using a SIMS and compared with an actual boron profile at the bonding interface of a bonded wafer to be estimated so as to determine one reference sample whose boron profile is equivalent to the actual boron profile of the bonded wafer to be estimated, and finally a dosage of boron in the determined reference sample is estimated by convertion to be a surface density of boron presenting at the bonding interface of the bonded wafer to be estimated at an initial stage prior to the bonding heat treatment of the bonded wafer to be estimated. Thus, the boron profile obtained by SIMS measurement can be converted into the boron surface density with the result that the boron quantity at the bonding interface of a bonded wafer can be readily estimated to be a boron surface density.

Method of estimating quantity of boron at bonding interface in bonded

A method is disclosed for obtaining bonded wafers of SOI type, where impurity redistribution in the bulk of the wafers is suppressed and the bonding strength between the wafers is substantially higher compared with that in the prior art. This is accomplished by forming a thermally grown oxide layer on the surface of the thinner one(bond wafer) of two monocrystalline silicon wafers having thicknesses different from each other by more than 50 .mu.m; then superposing the thinner wafer onto the other thicker wafer(base wafer); and finally conducting at least two heat treatments of the wafers at temperatures selected in the range of under 900.degree. C. for a period of time selected in the range of from 0.5 min. to 120 min.

Method of making bonded wafers

There is provided an SOI (Silicon On Insulator) substrate having a thick SOI layer, where crystallographic defects mainly consisting of OSFs (Oxidation Induced Stacking Fault) are practically prevented from occurrence in the SOI layer, according to the present invention. The manufacturing method for the SOI substrate according to the present invention comprises the following steps of: the silicon oxide film being formed by thermal oxidation on the surface of a first silicon wafer having a concentration of interstitial oxygen under 16 ppma (per JEIDA Standard); the first silicon wafer being superimposed on a second silicon wafer, which is a support for supporting the first silicon wafer, with the silicon oxide film sandwiched therebetween; then the superimposed wafers being heat-treated so as to obtain a bonded wafer; and further the bulk of the first silicon wafer of the bonded wafer being reduced by grinding and then polishing so as to obtain the SOI substrate with the SOI layer of more than 5 .mu.m in thickness, which is a single crystal layer, formed on the second silicon wafer.

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Takasaki, Japan

Masatake Katayama