  We present a phenomenological analysis of production and decays of stops,
sbottoms, and staus in e+e- collisions with sqrt(s) = 500 - 800 GeV. We include
SUSY-QCD and Yukawa coupling corrections as well as initial state radiation. We
show that e- beam polarization is a powerful tool for a determination of the
underlying SUSY parameters. Using in addition a polarized e+ beam improves the
precision of the parameter determination by about 25%.
