3d semiconductor device with isolation layers

A 3D semiconductor device, the device comprising:

• a first level comprising a plurality of first metal layers;
• a second level,
• wherein said second level is overlaying said first level,
• wherein said second level comprises at least one single crystal silicon layer,
• wherein said second level comprises a plurality of transistors,
• wherein each of said plurality of transistors comprises a single crystal channel,
• wherein said second level comprises a plurality of second metal layers,
• wherein said plurality of second metal layers comprise interconnections between said plurality of transistors,
• wherein said second level is overlaid by a first isolation layer;
• and
• a connective path between said plurality of transistors and said plurality of first metal layers,
• wherein said connective path comprises a via disposed through at least said single crystal silicon layer, and
• wherein said single crystal silicon layer has a thickness of less than 2,000 nm and greater than 5 nm.

A 3D semiconductor device, the device comprising:

• a first level comprising a plurality of first metal layers;
• a second level,
• wherein said second level is overlaying said first level,
• wherein said second level comprises at least one single crystal silicon layer,
• wherein said second level comprise a plurality of first transistors,
• wherein each of said plurality of first transistors comprises a single crystal channel,
• wherein said second level comprises a plurality of second metal layers,
• wherein said plurality of second metal layers comprise interconnections between said plurality of first transistors,
• wherein said second level is overlaid by a first isolation layer;
• a connective path between said plurality of first transistors and said plurality of first metal layers,
• wherein said connective path comprises a via disposed through said single crystal silicon layer, and
• a third level comprising single crystal second transistors,
• wherein said first isolation layer is overlaid by said third level,
• wherein said third level is overlaid by a second isolation layer,
• wherein said third level is bonded to said second isolation layer, and
• wherein said bonded comprises at least one oxide to oxide bond.