Methods of forming a photovoltaic cell
View Patent ↗In some embodiments, a method of forming a photovoltaic cell includes (1) forming a cleave plane in a donor body so as to define a lamina to be bonded to a receiver element and exfoliated from the donor body; (2) prior to bonding, pre-heating the donor body without the receiver element to a temperature of greater than about 200° C. for a first time period that is less than a time period required for exfoliation of the lamina from the donor body; (3) cooling the donor body after pre-heating the donor body; (4) bonding the donor body to the receiver element; and (5) heating the bonded donor body and receiver element for a second time period so as to complete the exfoliation of the lamina from the donor body. Numerous other aspects are provided.
1. A method comprising:
forming a cleave plane in a donor body so as to define a lamina to be bonded to a receiver element and exfoliated from the donor body;
after forming the cleave plane, pre-heating the donor body in a first chamber in an inert environment for a first time period that is less than a time period required for exfoliation of the lamina from the donor body, wherein the first chamber is a batch chamber capable of pre-heating two or more donor bodies at once, wherein pre-heating is performed at a temperature in the range from about 350 to about 500° C.;
after pre-heating the donor body, heating the donor body and the receiver element in a second chamber;
bonding the donor body to the receiver element within the second chamber; and
heating the bonded donor body and receiver element for a second time period so as to complete the exfoliation of the lamina from the donor body;
wherein the first time period is from about 5 minutes to about 4 hours and wherein the second time period is from about 2 to about 60 minutes.
2. The method of claim 1 wherein heating the bonded donor body and receiver element is performed in the second chamber.
3. The method of claim 1 wherein heating the bonded donor body and receiver element is performed in a third chamber.
4. The method of claim 1 and wherein at least one of bonding and heating the bonded donor body and receiver element is performed at a temperature in the range of about 400 to about 475° C.
5. A method of forming a photovoltaic cell, the method comprising:
providing a semiconductor donor body;
implanting a species into the donor body so as to form a cleave plane in the donor body, the cleave plane defining a lamina to be bonded to a receiver element and exfoliated from the donor body;
after the implanting step, pre-heating the donor body in an inert environment in a first chamber, wherein the first chamber is a batch chamber capable of pre-heating two or more donor bodies at once, for a first time period that is less than a time period required for exfoliation of the lamina from the donor body;
after pre-heating the donor body, heating the donor body and the receiver element in a second chamber;
bonding the donor body to the receiver element within the second chamber; and
heating the bonded donor body and receiver element for a second time period so as to complete the exfoliation of the lamina from the donor body;
wherein the first time period is at least as long as the second time period.
6. The method of claim 5 further comprising fabricating the photovoltaic cell using at least a portion of the lamina.
7. The method of claim 5 wherein the first time period is at least three times as long as the second time period.
8. The method of claim 7 wherein the first time period is at least six times as long as the second time period.
9. The method of claim 5 wherein preheating is performed at a first temperature and heating the bonded donor body and receiver element is performed at a second temperature that is less than or equal to the first temperature.