Sheet resistivity measurements of thin-film resistive overlays on silicon diode array camera tube targets

A new technique has been developed to measure the sheet resistivity of the silicon diode array target resistive overlay in a completed camera tube. The technique measures the sheet resistivity by determining the voltage profile on the oxide area surrounding the diode array area. The oxide voltage profile is set up by charge spreading out from the oxide to the diode array area. This "charge spreading" technique is believed to be accurate to within ±20 percent for sheet resistivities in the range of 10
¹⁰
-5 × 10
¹⁵
Ω/□. The sheet resistivity measurements are correlated with the resolution capabilities of the silicon diode array camera tube.