is an activation energy of 1 38 ev it is well known that activation energy for dislocation glide in the sige system is approximately 2 25 ev and not the extracted value of 1 38 ev this discrepancy occurs since the extracted value assumes that the effective strain is constant with temperature when in reality it is not thus if one desires to use the formulations described herein one must account for the change in effective strain with temperature fig4 is a plot of the effective strain calculated using equation 2 under the assumption that the activation energy for dislocation glide is 2 25 ev the effective strain drops with increasing growth temperature and is approximately in the 1 u00d7 10 u2212 4 u2212 3 u00d7 10 u2212 4 range for growths above 750 u00b0 c it is also clear from fig3 and 4 that for growth temperatures equal to or greater than 1000 u00b0 c dislocation densities much less than 10 5 cm u2212 2 are possible however as was stipulated previously such high growth temperatures using high concentrations of germane in the gas flow desired for high economical growth rates results in disastrous gas phase nucleation using the invention one can grow at reasonable growth rates at 750 u00b0 c avoid gas phase nucleation but achieve lower threading dislocation densities by annealing at a higher temperature without gas flow fig5 demonstrates the effect annealing can have on dislocation density by summarizing etch pit density epd measurements for sige samples grown with and without a post epi high temperature anneal the samples are 20 sige layers on sige graded buffers graded from 0 20 at a rate of 10 ge u03bcm the threading dislocation densities in the sige were measured as grown growth.