Growth temperature dependence for the formation of vacancy clusters in Si/Si[sub 0.64]Ge[sub 0.36]/Si structures.

The incorporation of vacancy clusters and vacancy point defects during the growth of Si/Si[sub 0.64]Ge[sub 0.36]/Si structures has been observed for growth temperatures between 250 °C and 550 °C using positron annihilation spectroscopy. A strong correlation between the electrical characteristics of the structures and the size and concentration of the clusters is observed. For the onset of two-dimensional hole gas behavior, a defect concentration less than 5x10[sup 16] cm[sup -3] is required. A further reduction in concentration below 1x10[sup 16] cm[sup -3] results in optimum electrical performance. The depth at which defects are observed increases with decreasing growth temperature indicating defect mobility during growth or subsequent annealing. © 2001 American Institute of Physics. [ABSTRACT FROM AUTHOR]