Abstract: A method for manufacturing a bonded wafer, in which when a bonded wafer is manufactured using an ion implantation separation method, impurities attached in the ion implantation step can be removed effectively, and less failure called a void is generated on the bonding surface. Impurities such as particles or organic substances attached in ion implantation step (c) are removed using a physical removal method (d). The surface of a first wafer (1) subjected to impurities removal is closely contacted onto the surface of a second wafer (2) for heat treatment (e). The first wafer is separated in a thin-film form at a micro bubble layer (f).

Abstract: A silicon oxide film 3′, 3″ is formed on each of the main surfaces of a first silicon single crystal substrate 1 (bond wafer) and a second silicon single crystal substrate 2 (base wafer), and the first and second silicon single crystal substrates are then brought into close contact so as to locate the silicon oxide films 3′, 3″ in between in an atmosphere of a clean air supplied through a boron-releasable filter, to thereby produce an SOI wafer 10. The second silicon single crystal substrate 2 employed herein comprises a silicon single crystal substrate having a bulk resistivity of 100 &OHgr;·cm or above. In thus produced SOI wafer 10, the silicon oxide film 3 has a depth profile of boron concentration in which the boron concentration reaches maximum at a thickness-wise position. This ensures manufacturing of SOI wafer excellent in high-frequency characteristics.

Abstract: A method for manufacturing a bonded wafer, in which when a bonded wafer is manufactured using an ion implantation separation method, impurities attached in the ion implantation step can be removed effectively, and less failure called a void is generated on the bonding surface.

Abstract: According to the present invention, there are provided an SO wafer wherein surface roughness of an SOI layer surface of the SOI wafer is 0.12 nm or less in terms of RMS value and/or interface roughness of an interface between the SOT layer and a buried oxide layer of the SOI wafer is 0.12 nm or less in terms of RMS value, and a method for producing an SOI wafer, which comprises mirror-polishing an SOI wafer, removing a native oxide film on a surface of the wafer or forming a thermal oxide film having a thickness of 300 nm or more on the surface and removing the thermal oxide film, and subjecting the wafer to a heat treatment in an atmosphere of 100% hydrogen or a mixed gas atmosphere of argon and/or nitrogen containing 10% or more of hydrogen by using a rapid heating and rapid cooling apparatus.

Abstract: There is provided a method of fabricating an SOI wafer having high quality by hydrogen ion delamination method wherein a damage layer remaining on the surface of the SOI layer after delamination and surface roughness are removed maintaining thickness uniformity of the SOI layer. According to the present invention, there are provided a method of fabricating an SOI wafer by hydrogen ion delamination method wherein an oxide film is formed on an SOI layer by heat treatment in an oxidizing atmosphere after bonding heat treatment, then the oxide film is removed, and subsequently heat treatment in a reducing atmosphere is performed; a method of fabricating an SOI wafer by hydrogen ion delamination method wherein an oxide film is formed on an SOI layer by heat treatment in an oxidizing atmosphere after delaminating heat treatment, then the oxide film is removed, and subsequently heat treatment in a reducing atmosphere is performed; and an SOI wafer fabricated by the methods.

Abstract: There is disclosed a method of fabricating an SOI wafer by a hydrogen ion delamination method wherein a surface of an SOI layer is not polished but is subjected to heat treatment in a reducing atmosphere containing hydrogen after a bonding heat treatment, a method of fabricating an SOI wafer by a hydrogen ion delamination method wherein a surface of an SOI layer is not polished but subjected to heat treatment in a reducing atmosphere containing hydrogen after delaminating heat treatment, and a SOI wafer fabricated by the methods. There are provided a method of fabricating an SOI wafer by a hydrogen ion delamination method wherein a damage layer remaining on the surface of the SOI layer after delamination is removed and surface roughness is improved without polishing, so that uniform thickness of the SOI layer can be achieved, and to simplify the process therefor.

Abstract: There is disclosed a method of fabricating an SOI wafer wherein an oxide film is formed on at least one of two single crystal silicon wafers; hydrogen ions or rare gas ions are implanted into the upper surface of one of the two silicon wafers in order to form an ion implanted layer; the ion-implanted surface is brought into close contact with the surface of the other silicon wafer via the oxide film; heat treatment is performed to separate a thin film from the silicon wafer with using the ion implanted layer as a delaminating plane to fabricate the SOI wafer having an SOI layer; and then an epitaxial layer is grown on the SOI layer to form a thick SOI layer. There is provided an SOI wafer which has a thick SOI layer with good thickness uniformity and good crystallinity and which is useful for a bipolar device or a power device.

Abstract: The object of the invention is to provide a bonded wafer in which an inferior bonding state of the bonded wafer attained by a hydrogen ion delamination method is reduced, no separation or no void is found at the connecting interface under a superior production characteristic and in a low cost. In a method for manufacturing a bonded wafer by a hydrogen ion delamination method, carbon concentration at a close contacted surface where both wafers are closely contacted from each other is 3-1014 atoms/cm2 or less.

Abstract: There is disclosed a method of fabricating an SOI wafer in which a bond wafer to form a SOI layer and a base wafer to be a supporting substrate are prepared; an oxide film is formed on at least the bond wafer; hydrogen ions or rare gas ions are implanted in the bond wafer via the oxide film in order to form a fine bubble layer (enclosed layer) within the bond wafer; the ion-implanted surface is brought into close contact with the surface of the base wafer; and then heat treatment is performed to separate a thin film from the bond wafer with using the fine bubble layer as a delaminating plane to fabricate the SOI wafer having an SOI layer; and wherein deviation in the thickness of the oxide film formed on the bond wafer is controlled to be smaller than the deviation in the ion implantation depth, and the SOI wafer fabricated thereby. There is provided an SOI wafer which has an SOI layer having improved thickness uniformity.

Abstract: There is disclosed a method of recycling a delaminated wafer produced as a by-product in producing an SOI wafer according to a hydrogen ion delaminating method by reprocessing it for reuse as a silicon wafer, wherein at least polishing of the delaminated wafer for removing of a step in the peripheral part of the delaminated wafer and heat treatment in a reducing atmosphere containing hydrogen are conducted as the reprocessing. There are provided a method of appropriately reprocessing a delaminated wafer produced as a by-product in a hydrogen ion delaminating method to reuse it as a silicon wafer actually, and particularly, a method of reprocessing an expensive wafer such as an epitaxial wafer many times for reuse, to improve productivity of SOI wafer having a high quality SOI layer, and to reduce producing cost.

Abstract: There is disclosed a method of fabricating an SOI wafer wherein an oxide film is formed on at least one of two single crystal silicon wafers; hydrogen ions or rare gas ions are implanted into the upper surface of one of the two silicon wafers in order to form an ion implanted layer; the ion-implanted surface is brought into close contact with the surface of the other silicon wafer via the oxide film; heat treatment is performed to separate a thin film from the silicon wafer with using the ion implanted layer as a delaminating plane to fabricate the SOI wafer having an SOI layer; and then an epitaxial layer is grown on the SOI layer to form a thick SOI layer. There is provided an SOI wafer which has a thick SOI layer with good thickness uniformity and good crystallinity and which is useful for a bipolar device or a power device.

Abstract: There is disclosed a method of recycling a delaminated wafer produced as a by-product in producing an SOI wafer according to a hydrogen ion delaminating method by reprocessing it for reuse as a silicon wafer, wherein at least polishing of the delaminated wafer for removing of a step in the peripheral part of the delaminated wafer and heat treatment in a reducing atmosphere containing hydrogen are conducted as the reprocessing. There are provided a method of appropriately reprocessing a delaminated wafer produced as a by-product in a hydrogen ion delaminating method to reuse it as a silicon wafer actually, and particularly, a method of reprocessing an expensive wafer such as an epitaxial wafer many times for reuse, to improve productivity of SOI wafer having a high quality SOI layer, and to reduce producing cost.

Abstract: There is disclosed a method of fabricating an SOI wafer in which a bond wafer to form a SOI layer and a base wafer to be a supporting substrate are prepared; an oxide film is formed on at least the bond wafer; hydrogen ions or rare gas ions are implanted in the bond wafer via the oxide film in order to form a fine bubble layer (enclosed layer) within the bond wafer; the ion-implanted surface is brought into close contact with the surface of the base wafer; and then heat treatment is performed to separate a thin film from the bond wafer with using the fine bubble layer as a delaminating plane to fabricate the SOI wafer having an SOI layer; and wherein deviation in the thickness of the oxide film formed on the bond wafer is controlled to be smaller than the deviation in the ion implantation depth, and the SOI wafer fabricated thereby. There is provided an SOI wafer which has an SOI layer having improved thickness uniformity.

Abstract: There is disclosed a method of fabricating an SOI wafer in which a bond wafer to form a SOI layer and a base wafer to be a supporting substrate are prepared; an oxide film is formed on at least the bond wafer; hydrogen ions or rare gas ions are implanted in the bond wafer via the oxide film in order to form a fine bubble layer (enclosed layer) within the bond wafer; the ion-implanted surface is brought into close contact with the surface of the base wafer; and then heat treatment is performed to separate a thin film from the bond wafer using the fine bubble layer as a delaminating plane to fabricate the SOI wafer having an SOI layer; and wherein deviation in the thickness of the oxide film formed on the bond wafer is controlled to be smaller than the deviation in the ion implantation depth, and the SOI wafer fabricated thereby. There is provided an SOI wafer which has an SOI layer having improved thickness uniformity.

Abstract: A method for heat-treating an SOI wafer in a reducing atmosphere, wherein the SOI wafer is heat-treated through use of a rapid thermal annealer at a temperature within the range of 1100° C. to 1300° C. for 1 sec to 60 sec. The reducing atmosphere is preferably an atmosphere of 100% hydrogen or a mixed gas atmosphere containing hydrogen and argon. The heat treatment is preferably performed for 1 sec to 30 sec. The method eliminates COPs in an SOI layer of an SOI wafer in accordance with a hydrogen annealing method, while preventing etching of the SOI layer and a buried oxide layer.

Abstract: In a method of fabricating a bonded wafer, an oxide film is first formed on the surface of at least one of two mirror-polished silicon wafers. The two silicon wafers are superposed such that the mirror-polished surfaces come into close contact with each other, and heat treatment is performed in order to join the wafers together firmly. Subsequently, the thickness of one of the wafers is reduced so as to yield a thin film, the surface of which is then polished and subjected to vapor-phase etching in order to make the thickness of the thin film uniform. Optionally, the vapor-phase-etched surface is then mirror-polished. The surface of the bonded wafer is oxidized, and the generated surface oxide film is then removed. In the method, the thickness of the oxide film formed on the surface of the bonded wafer is made not greater than 50 nm.

Abstract: In a method of fabricating an SOI wafer, an oxide film is formed on the surface of at least one of two silicon wafers; hydrogen ions or rare gas ions are implanted into the upper surface of one of the two silicon wafers in order to form a fine bubble layer (enclosed layer) within the wafer; the ion-implanted silicon wafer is superposed on the other silicon wafer such that the ion-implanted surface comes into close contact with the surface of the other silicon wafer via the oxide film; heat treatment is performed in order to delaminate a portion of the ion-implanted wafer while the fine bubble layer is used as a delaminating plane, in order to form a thin film to thereby obtain an SOI wafer. In the method, a defect layer at the delaminated surface of the thus-obtained SOI wafer is removed to a depth of 200 nm or more through vapor-phase etching, and then mirror polishing is performed. Therefore, the obtained SOI wafer has an extremely low level of defects and a high thickness uniformity.

Abstract: A method for manufacturing a bonded wafer comprises the steps of; mirror-polishing a surface of first and second substrates, bringing the mirror-polished surfaces of the substrates contact with each other to join them, and subjecting the substrates to a heat treatment to firmly bond them. One of the surfaces of the first and second substrates prior to bonding, or one surface of the bonded wafer is subjected to a polishing treatment for exerting little influence by irregularities on a rear surface of the one substrate or by a figure of a surface of a polishing plate which is in contact with the rear surface of the one substrate.

Abstract: 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.