3d semiconductor device and structure

A 3D semiconductor device, the device comprising:

• a first level comprising single crystal first transistors, and a first metal layer,
• wherein said first level is overlaid by a first isolation layer;
• a second level comprising second transistors,
• wherein said first isolation layer is overlaid by said second level, and
• wherein said second level is overlaid by a second isolation layer;
• a third level comprising single crystal third transistors,
• wherein said second isolation layer is overlaid by said third level,
• wherein said third level is overlaid by a third isolation layer,
• wherein said second level is bonded to said first isolation layer,
• wherein said bonded comprises at least one oxide to oxide bond, and
• wherein said bonded comprises at least one metal to metal bond.

A 3D semiconductor device, the device comprising:

• a first level comprising first transistors,
• wherein said first level is overlaid by a first isolation layer;
• a second level comprising second transistors,
• wherein said first isolation layer is overlaid by said second level, and
• wherein said second level is overlaid by a second isolation layer;
• a third level comprising third transistors,
• wherein said second isolation layer is overlaid by said third level,
• wherein said third level is overlaid by a third isolation layer,
• a fourth level comprising single crystal third transistors,
• wherein said third isolation layer is overlaid by said fourth level,
• wherein said fourth level is overlaid by a fourth isolation layer,
• wherein said fourth level is bonded to said third isolation layer,
• wherein said bonded comprises at least one oxide to oxide bond, and
• wherein said bonded comprises at least one metal to metal bond.