In the deposition of cubic boron nitride (cBN) films by DC-bias-assisted DC jet chemical vapor deposition in an Ar-N2-BF3-H-2 gas system; the balance between growth and etching and its relation to the deposition conditions were investigated A step process was designed to optimize the nucleation and growth separately, and a critical bias voltage for the growth after nucleation was observed. It was found that etching occurred when the bias voltage was below this critical value. Under optimized conditions, the crystallinity and crystal size of the cBN films were improved during the second step. Furthermore, cBN films showing clear crystal facets were obtained.