Hafnium tantalum nitride resistive sea for the silicon diode-array camera tube target

A new material has been developed as a resistive sea for the silicon diode-array camera tube target. The material is prepared by reactive sputtering of a hafnium tantalum cathode in a nitrogen atmosphere. By adjusting the relative amounts of hafnium and tantalum in the cathode or by changing the sputtering parameters, the resistivity of the hafnium tantalum nitride sea may be optimized. The nitride may be heated to 350°C during camera tube bakeout with no degradation in performance. By controlling the film deposition conditions, electrostatic focus camera tubes have been made with excellent aging, dark current, lag, and resolution characteristics.