Trap rich layer formation techniques for semiconductor devices
View Patent ↗A trap rich layer for an integrated circuit chip is formed by chemical etching and/or laser texturing of a surface of a semiconductor layer. In some embodiments, a trap rich layer is formed by a technique selected from the group of techniques consisting of laser texturing, chemical etch, irradiation, nanocavity formation, porous Si-etch, semi-insulating polysilicon, thermal stress relief and mechanical texturing. Additionally, combinations of two or more of these techniques may be used to form a trap rich layer.
1. A method comprising:
forming a damaged layer for an integrated circuit by scanning a laser beam in a pattern across a first wafer;
forming a circuit layer for the integrated circuit in a second wafer; and
bonding the first wafer to a top side of the second wafer;
wherein the damaged layer has a trap density of greater than 10 11 cm −2 eV −1 ; and
wherein the damaged layer is located between the circuit layer and a substrate of the integrated circuit.
2. The method of claim 1 , wherein:
the damaged layer is formed after the circuit layer is formed.
3. The method of claim 1 , wherein:
the pattern is a serpentine pattern; and
the damaged layer is formed on a surface of the first wafer.
4. The method of claim 1 , further comprising:
wherein the damaged layer is formed across an entire surface of the first wafer.
5. The method of claim 1 , wherein:
the damaged layer is formed in the first wafer before the circuit layer is formed in the second wafer.
6. The method of claim 5 , further comprising:
forming a buried insulator for a silicon-on-insulator structure in the second wafer before forming the damaged layer;
wherein the integrated circuit comprise the silicon-on-insulator structure.
7. A method comprising:
forming a trap rich layer in a first wafer for an integrated circuit using a laser beam; and
forming a circuit layer in a second wafer for the integrated circuit; and
bonding the first wafer to a top side of the second wafer;
wherein the trap rich layer is located between the circuit layer and a substrate of the integrated circuit after the bonding; and
wherein the trap rich layer is formed after the circuit layer is formed.
8. The method of claim 7 , wherein:
the second wafer comprises a silicon-on-insulator wafer.
9. The method of claim 8 , further comprising:
thinning a substrate of the silicon-on-insulator wafer using an etchant or chemical mechanical polish.
10. The method of claim 8 ,
wherein the trap rich layer is formed on a surface of the first wafer; and
wherein the surface of the first wafer is bonded to the silicon-on-insulator wafer during the bonding.
11. The method of claim 7 , wherein:
the trap rich layer has a trap density of greater than 10 11 cm −2 eV −1 .
12. The method of claim 7 , wherein:
the first wafer comprises a bulk semiconductor wafer.
13. A method comprising,
forming a trap rich layer for an integrated circuit using a laser beam on a first semiconductor wafer;
forming a circuit layer for the integrated circuit on a second semiconductor wafer; and
bonding the first semiconductor wafer to a top side of the second semiconductor wafer;
wherein the trap rich layer is located between the circuit layer and a substrate of the integrated circuit after the bonding; and
wherein the circuit layer is formed after the trap rich layer is formed.
14. The method of claim 13 , wherein:
the second semiconductor wafer comprises a silicon-on-insulator wafer.
15. The method of claim 13 , further comprising:
forming a buried insulator for the silicon-on-insulator wafer after forming the trap rich layer.
16. The method of claim 13 , wherein:
wherein the trap rich layer has a trap density of greater than 10 11 cm −2 eV −1 .
17. The method of claim 13 , further comprising:
the first semiconductor wafer comprises a bulk semiconductor wafer.
18. The method of claim 13 further comprising:
forming a transistor and one or more metal layers within the circuit layer on the second semiconductor wafer.