Apparatus for stressing semiconductor substrates
Apparatus for use in preparing heterostructures having a reduced concentration of defects including apparatus for stressing semiconductor substrates to allow them to conform to a crystal having a different crystal lattice constant.
1. An apparatus for radially compressing or distending a semiconductor structure having a front surface, a back surface, a circumferential edge and a central axis, the semiconductor structure consisting essentially of (1) a silicon substrate or (2) a silicon substrate having an epitaxial layer disposed on a surface of the substrate, the apparatus comprising:
a chamber;
a heater for heating the chamber, the heater comprising radiant heating lamps, resistance heaters or inductive heaters;
a stressor configured to radially compress or distend the structure, the stressor being disposed entirely within the chamber, the stressor comprising triangular-shaped segments mounted in the chamber that point inward to a central axis, the segments being configured for movement radially inward or outward from the central axis to cause the structure to radially compress or distend to stress the structure, the stress being directed perpendicularly to the central axis; and
fluid passageways formed in each segment for forming a vacuum between the segment and structure and wherein the segments are driven by pneumatics, hydraulics, or a motor.
2. The apparatus as set forth in claim 1 wherein the segments are configured for movement radially inward from the central axis to cause the structure to radially compress.
3. The apparatus as set forth in claim 1 wherein the segments are configured for movement radially outward from the central axis to cause the structure to radially distend.
4. The apparatus as set forth in claim 1 wherein the heater is external to the chamber.
5. The apparatus as set forth in claim 1 wherein the front surface of the semiconductor structure is planar.
6. The apparatus as set forth in claim 1 in combination with the semiconductor structure, the semiconductor structure consisting essentially of a silicon substrate.
7. The apparatus as set forth in claim 1 in combination with the semiconductor structure, the semiconductor structure consisting essentially of a silicon substrate having an epitaxial layer disposed on a surface of the substrate.