Transfer of a thin layer from a wafer comprising a buffer layer

A method of preparing a semiconductor wafer, comprising:

• growing a first layer of a first material in a strained state on a matching substrate comprising a matching layer;
• growing a second layer of a semiconductor second material, different from the first material, in a relaxed state on the first layer to form a boundary between the first and second layers and to form a composite structure which comprises the matching, first, and second layers, wherein the first and second layers each have substantially the same first lattice parameter;
• creating a region of weakness in the matching substrate to facilitate splitting;
• splitting the composite structure at the region of weakness into:
• an unfinished wafer that includes the second layer, the first layer, and at least a remaining portion of the matching layer, and
• a handle wafer:
• removing the remaining portion of the matching layer from the first layer;
• and
• removing the first layer from the second layer to produce a surface on the second layer that is substantially smooth and of substantially uniform thickness.