Improved Process for Fabrication of Multi-Beam Cathode Ray Tube Device Chips
Original Publication Date: 1984-Jun-01
Included in the Prior Art Database: 2005-Feb-04
The invention consists of combining ion beam etching with chemical or ion etching of tungsten (W) to sputter clean the sapphire surface between the tungsten cathode and grid structures. The surface resistivity is greatly increased, and remains high after activating the cathode emitter surface at 800ŒC. This combined process solves the contamination problem which remains after the current process of chemical etching of the W pattern. For proper operation, the sapphire surface between the cathode and grid structures must have high sheet resistance (2 x 1010 ohms per square, equal to about 80 M ohms here). With the current processing technique, the emitter resist material, containing Ba, Ca, Sr carbonates, is coated onto a W layer patterned by chemical etching.