The parameter space for the heteroepitaxial nucleation of diamond on Si(001) using the bias process was studied by x-ray diffraction texture measurements. It was found that heteroepitaxial orientation can be achieved over a wide range of different parameters provided that the bias time is within a definite time interval. It was observed thattwidth,the width of the time window, andtopt ,the bias time for optimal azimuthal alignment, strongly decrease with the absolute value of the bias voltage. For high bias voltages an extremely low value oftopt(20 s at −300 V) was found. Applying the bias conditions longer thantoptresulted in a strong decrease of the pole density maxima of the heteroepitaxial grains accompanied by a significant broadening of their azimuthal distribution that is interpreted in terms of two different routes for the loss of epitaxy. The different time constants characterizing the process window for a fixed bias voltage are traced back to feedback of the growing film on the plasma and on the electrical field distribution above the substrate. ©1997 American Institute of Physics.