Measurement of Lattice Strain and Relaxation Effects in Strained Silicon Using X-ray Diffraction and Convergent Beam Electron Diffraction (open access)

Measurement of Lattice Strain and Relaxation Effects in Strained Silicon Using X-ray Diffraction and Convergent Beam Electron Diffraction

The semiconductor industry has decreased silicon-based device feature sizes dramatically over the last two decades for improved performance. However, current technology has approached the limit of achievable enhancement via this method. Therefore, other techniques, including introducing stress into the silicon structure, are being used to further advance device performance. While these methods produce successful results, there is not a proven reliable method for stress and strain measurements on the nanometer scale characteristic of these devices. The ability to correlate local strain values with processing parameters and device performance would allow for more rapid improvements and better process control. In this research, x-ray diffraction and convergent beam electron diffraction have been utilized to quantify the strain behavior of simple and complex strained silicon-based systems. While the stress relaxation caused by thinning of the strained structures to electron transparency complicates these measurements, it has been quantified and shows reasonable agreement with expected values. The relaxation values have been incorporated into the strain determination from relative shifts in the higher order Laue zone lines visible in convergent beam electron diffraction patterns. The local strain values determined using three incident electron beam directions with different degrees of tilt relative to the device structure have …
Date: August 2007
Creator: Diercks, David Robert
System: The UNT Digital Library