BACKGROUND:  The exponential decrease in transistor size has been the driving force behind the increasing performance and rapid growth of information technology; however, continued scaling through the current standard manufacturing practices employed by the semiconductor industry will result in reduced performance. Although, one method to improve performance without replacing silicon with expensive materials, is to enhance carrier mobility by applying strain to silicon; the current strain techniques suffer from dislocation, resulting in non-uniform strain, non-flat surface morphology, and strain relaxation, which in turn reduce the mobility enhancement.

INNOVATION:  Researchers at UCLA have developed a method to fabricate strained Si thin films without introducing dislocation. The method utilizes a bi-layer system that consists of a stressor layer attached to a thin silicon film. Dislocation is avoided by limiting the thickness of the Si layer to a critical value that depends on stressor material and strain level. Furthermore, the achievable strain level in silicon is controllable and can even be larger than that achievable in the stressor layer.

POTENTIAL APPLICATIONS 

• Silicon-based electronics

ADVANTAGES

• Dislocation-free strained silicon
• Compatible with current silicon-based technology
• Controllable strain level

Reference: UCLA Case No. 2006-004

Patent Application: US/07/0017438