Growth temperature dependence for the formation of vacancy clusters in Si/Si0.64Ge0.36/Si structures

The incorporation of vacancy clusters and vacancy point defects during the growth of Si/Si0.64Ge0.36/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 5×1016 cm−3 is required. A further reduction in concentration below 1×1016 cm−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.

Growth temperature dependence for the formation of vacancy clusters in Si/Si0.64Ge0.36/Si structures Journal Articles