Study of field emission arrays for travelling wave tubes

The Spindle type FEAs were fabricated using n-type silicon wafers with different resistivities. The I-V measurements and emission characteristics of FEAs made from high resistivity wafers indicated that the emission performance was greatly improved. The FEAs were coated with a thin layer of nanocrystalline diamond film (NCD) using microwave plasma chemical vapour deposition (MPCVD). Scanning electron microscopy (SEM) observations of FEAs were made before coating NCD and after coating NCD.