Several focusing field emission devices are simulated by the MAGIC particle
-in-cell code program. The emission current, anode current, and focusing ef
fect are compared and analyzed. The results show that the coaxial focusing
structure has the smallest electron dispersion width, the coplanar focusing
structure has good focusing effect and simplest fabrication process, and t
he ridge focusing structure has the largest anode current. The overall cons
ideration reveals that the coplanar focusing structure is the better choice
for display application. (C) 2000 American Vacuum Society. [S0734-211X(00)
07402-3].