Sc. Jain et al., EFFECT OF ELASTIC-CONSTANTS ON THE STRESSES IN STRIPES AND SUBSTRATES- A 2D FE CALCULATION, Semiconductor science and technology, 13(8), 1998, pp. 864-870
We report results of the finite element (FE) calculations of strains a
nd stresses in stripe-substrate (S-S) heterostructures for several val
ues of Young's moduli (E-t for the stripe and E-s for the substrate),
stripe halfwidth l and its thickness h. The normalized stress sigma(xx
)/sigma(0) (ob is the stress in the large area layer where effect of e
dge induced relaxation is absent) in both the stripe and the substrate
depends only on the ratio R-E = E-f/E-s and not on the individual val
ues of E-f and E-s. Numerical values of sigma(xx)/sigma(0) are calcula
ted by the FE method for nine values of l/h and five values of R-E. It
is found that R-E has only a weak influence on the stress distributio
n. sigma(xx)/sigma(0) in both the stripes and the substrates decreases
monotonically and approximately linearly as RE increases. The values
reported in this paper can be used for other values of R-E, l and h by
interpolation without the need of making fresh FE calculations for ea
ch case. Experimental values of the stresses determined from the lumin
escence and the micro-Raman data support strongly the conclusion that
the dependence of stress on R-E is weak.