Bonded wafer and method of producing bonded wafer

The present invention provides a bonded wafer, wherein at least a silicon single crystal layer is formed on a silicon single crystal wafer, the silicon single crystal layer has a crystal plane orientation of {110}, and the silicon single crystal wafer has a crystal plane orientation of {100}. The present invention also provides a method of producing a bonded wafer, wherein after at least a first silicon single crystal wafer having a crystal plane orientation of {110} and a second silicon single crystal wafer having a crystal plane orientation of {100} are bonded directly or bonded via an insulator film, the first silicon single crystal wafer is made into a thin film. Thereby, there can be provided a wafer possible to obtain a MIS device having good characteristics by utilizing a silicon single crystal wafer having the {110} plane.