  We study the effect of time-delayed feedback control and Gaussian white noise
on the spatio-temporal charge dynamics in a semiconductor superlattice. The
system is prepared in a regime where the deterministic dynamics is close to a
global bifurcation, namely a saddle-node bifurcation on a limit cycle ({\it
SNIPER}). In the absence of control, noise can induce electron charge front
motion through the entire device, and coherence resonance is observed. We show
that with appropriate selection of the time-delayed feedback parameters the
effect of coherence resonance can either be enhanced or destroyed, and the
coherence of stochastic domain motion at low noise intensity is dramatically
increased. Additionally, the purely delay-induced dynamics in the system is
investigated, and a homoclinic bifurcation of a limit cycle is found.
