The Critical Thickness of Layers Subject to Anisotropic Misfit.

1991 ◽  
Vol 239 ◽  
Author(s):  
Richard Beanland
Keyword(s):  
Dislocation Density ◽  
Layer Thickness ◽  
Critical Thickness ◽  
Theoretical Calculations ◽  
Critical Layer ◽  
Epitaxial Layers ◽  
Misfit Dislocations ◽  
Critical Layer Thickness ◽  
New Formulation

ABSTRACTIt is well known that it becomes energetically favourable for misfit dislocations to be introduced into strained epitaxial layers above a certain ‘critical’ layer thickness, hc. To date, theoretical calculations of hc have only been made for cases of isotropie misfit - i.e. cases where the misfit is the same for every direction in the interface. Using a new formulation of the Frank-Bilby equation and the concept of coherency dislocations, it is now possible to treat cases of anisotropie misfit, such as silicon on sapphire (SOS). The method used to obtain the critical thickness is described, and values of hc and equilibrium dislocation density are given for various materials systems.

Extrinsic Gettering with Epitaxial Misfit Dislocations

1984 ◽  
Vol 36 ◽  
Author(s):  
Ali S. M. Salih ◽  
W. Maszara ◽  
H. J. Kim ◽  
G. A. Rozgonyi
Keyword(s):  
Dislocation Density ◽  
Leakage Current ◽  
Schottky Diode ◽  
Impurity Concentration ◽  
Active Surface ◽  
Epitaxial Layers ◽  
Misfit Dislocations ◽  
Chemical Analyses ◽  
Defect Reactions ◽  
Metallic Species

ABSTRACTNew results are presented on Ge doped Si epitaxial layers which contain interfacial misfit dislocations. Microscopic and chemical analyses showed the preferential gettering of several metallic species (Au, Cu, Ni, and Fe) at the misfit dislocations with semiquantitative correlation between dislocation density and the captured impurity concentration. Wafer curvature was measured and shown to be less than that for typical Si3N4 and SiO2 layers used in IC fabrication. The reduction of Schottky diode leakage current has been clearly demonstrated and attributed to gettering of residual impurities, as well as signifying that, the active surface device region is not deleteriously affected by spurious defect reactions at the buried epitaxial interface.

Modulation Structure and Superhardness Effect of VC/TiN Nano-Multilayer Films

2012 ◽  
Vol 184-185 ◽  
pp. 1080-1083
Author(s):  
Jian Ling Yue ◽  
Wei Shi ◽  
Ge Yang Li
Keyword(s):  
Elastic Modulus ◽  
Magnetron Sputtering ◽  
Layer Thickness ◽  
Coherent Structure ◽  
Multilayer Films ◽  
Critical Layer ◽  
Maximum Hardness ◽  
Critical Layer Thickness ◽  
The Relationship

A series of VC/TiN nano-multilayer films with various TiN layer thicknesses were synthesized by magnetron sputtering method. The relationship between the modulation structure and superhardness effect of the multilayer films were investigated. The results reveal that TiN below a critical layer thickness grows coherently with VC layers in multilayers. Correspondingly, the hardness and elastic modulus of the multilayers increase significantly. The maximum hardness and modulus achieved in these multilayers is 40.7GPa and 328GPa.With further increase in the TiN layer thickness, coherent structure of multilayers are destroyed, resulting in a remarkable decrease of hardness and modulus. The superhardness effect of multilayers is related to the three directional strains generated from the coherent structure.

Sign in / Sign up

Export Citation Format

Share Document