Enhancement in field emission of silicon microtips by bias-assisted carburization

Ultrathin carbon layers with thicknesses below 50 Angstrom have been deposi ted on silicon microtip arrays by bias-assisted carburization (BAC) using m icrowave plasma chemical vapor deposition. The tip radius of these silicon tips is reduced below 55 nm under low deposition temperature. The field emi ssion characterization has been performed in a high-vacuum environment. An enhancement in the field emission is observed of about 3 orders of magnitud e in BAC silicon microtips over untreated silicon microtips. With an applie d voltage of 1100 V, emission currents of 80 and 120 muA have been achieved for the films grown (at de bias of -200 V for 40 min) with 15% and 25% CH4 /H-2 gas ratio, respectively. An emission current of 40 muA has been achiev ed for the film grown (at de bias of -300 V for 30 min) with 3.5% CH4/H-2 r atio. The BAC silicon emitter has good emission stability at a constant vol tage of 1100 V. These investigations indicate that further improvement of t his technology will lead to simple and inexpensive field emission display d evices. (C) 2000 American Vacuum Society. [S0734-211X(00)10706-1].