Methods of transferring layers of material in 3d integration processes and related structures and devices

A method of fabricating a semiconductor device, comprising:

• transferring a layer of semiconductor material from a first donor structure to a second structure, comprising:
• implanting ions into the first donor structure to form a generally planar weakened zone within the first donor structure defined by the implanted ions, the generally planar weakened zone separating a layer of semiconductor material of the first donor structure from a remainder of the first donor structure, wherein at least one of a concentration of the implanted ions and an elemental composition of the implanted ions varies across the generally planar weakened zone in at least one direction parallel to the generally planar weakened zone;
• bonding the first donor structure to the second structure;
• and
• fracturing the first donor structure along the generally planar weakened zone and leaving the layer of semiconductor material bonded to the second structure;
• and
• fabricating a plurality of active device structures on the transferred layer of semiconductor material.