Silicon-on-silicon hybrid wafer assembly

DETAILED DESCRIPTION According to the present invention, a technique for applying a thin film of silicon material to a target, or handle, wafer is provided.
This technique separates thin films of material from a donor substrate by implanting particles,such as hydrogen ions, into the donor substrate, and then separating a thin film of material above the layer of implanted particles.
The thin film can be bonded to a target wafer that provides mechanical support to form a hybrid substrate before or after separation.
In a specific embodiment, the present invention provides a process for forming a film of material from a donor substrate, typically a single crystal of silicon, using a controlled cleaving process.
That process includes a step of introducing energetic particles (e.
g.
, charged or neutral molecules, atoms, or electrons having sufficient kinetic energy) through a surface of a donor substrate to a selected depth underneath the surface, where the particles are at a relatively high concentration to define a thickness of donor substrate material (e.
g.
, thin film of detachable material) above the selected depth.
The surface of the donor wafer is then typically attached to a target wafer, that will provide mechanical support for the thin film using a low-temperature bonding process.
The target wafer can be a single crystal, polycrystalline, or amorphous, depending on the desired hybrid wafer characteristics.
Energy is applied to a selected region of the donor substrate material to initiate a controlled cleaving action in the donor substrate, whereupon the cleaving action is made using a propagating cleave front(s) to free the donor material from a remaining portion of the donor substrate.
The thin film is then permanently bonded to the target wafer, typically with a high-temperature annealing process.
In another embodiment, a layer of microbubbles is formed at a selected depth in the substrate.
The substrate is globally heated and pressure in the bubbles eventually shatters the substrate material generally in the plane of the microbubbles, separating a thin film of silicon from the substrate