Local Oxidation of Silicon (LOCOS)
- Practical Electron Microscopy and Database -
- An Online Book -


This book (Practical Electron Microscopy and Database) is a reference for TEM and SEM students, operators, engineers, technicians, managers, and researchers.


In practice, the strain analysis method using CBED technique has been applied to study the lattice strain distribution around local oxidation of silicon (LOCOS) in semiconductor devices at nanometer-scale spatial resolutions (e.g. 10 nm in diameter). For instance, Figure 2411 (a) shows a cross-sectional TEM image of a measured LOCOS region. The white circles are the points where the lattice strains are measured by CBED and are plotted against the distance from the field edge shown in Figure 2411 (b). The positive values represent tensile strain, while the negative values represent compressive strain. The tensile strain εxx (the normal strain in the x-direction) is attributed to the difference between the thermal expansion coefficients (CTE) of Si and SiO2. The Si CTE is ten times larger than that of SiO2. The smaller compressive strain εyy (the normal strain in the y-direction) indicates that the tensile stress in the x-direction acts on εyy compressively as lateral strain. The share strain εxy at the field edges is large probably due to dislocations formed near the LOCOS structure.

Strain of Local Oxidation of Silicon (LOCOS)

Figure 2411. (a) Cross-sectional TEM image of measured LOCOS region, and (b) The distribution of strain components as functions of the distance from the field edge. The position of the field edge is indicated by a white arrow. [1]






[1] Akio Toda, Nobuyuki Ikarashi, Haruhiko Ono, Local lattice strain measurements in semiconductor devices by using convergent-beam electron diffraction, Journal of Crystal Growth 210 (2000) 341-345.




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