Gtat Corporation

Twin Creeks Technologies, Inc.

Orion Leland

Gopal Prabhu

Aditya Agarwal

Venkatesan Murali

Robert D Tolles

Thomas Edward Dinan, Jr

Kathy Jackson

A donor wafer, for example of silicon, has an irregular surface following cleaving of a lamina from the surface, for example by exfoliation following implant of hydrogen and/or helium ions to define a cleave plane. Pinholes in the lamina leave column asperities at the exfoliated surface of the donor wafer, and the beveled edge may leave an edge asperity which fails to exfoliate. To prepare the surface of the donor wafer for reuse, mechanical grinding removes the column and edge asperities, and minimal additional thickness. Following cleaning, growth and removal of an oxide layer at the surface rounds remaining peaks. The smoothed surface is well adapted to bonding to a receiver element and exfoliation of a new lamina. A variety of devices may be fabricated from the lamina, for example a photovoltaic cell.

Method for preparing a donor surface for reuse

The invention provides for a semiconductor wafer with a metal support element suitable for the formation of a flexible or sag tolerant photovoltaic cell. A method for forming a photovoltaic cell may comprise providing a semiconductor wafer have a thickness greater than 150 &#x3bc;m, the wafer having a first surface and a second surface opposite the first and etching the semiconductor wafer a first time so that the first etching reduces the thickness of the semiconductor wafer to less than 150 &#x3bc;m. After the wafer has been etched a first time, a metal support element may be constructed on or over the first surface; and a photovoltaic cell may be fabricated, wherein the semiconductor wafer comprises the base of the photovoltaic cell.

Method for forming flexible solar cells

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&#xb0; 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.

Methods of forming a photovoltaic cell

Growing community of inventors

Fremont, CA, United States of America

Orion Leland