A lateral-type polysilicon field emission trio-de, consisting of two symmetric gate tips aligned by a 70degrees angle with respect to sharp cathode tips, was fabricated by using the local oxidation of polysilicon process. The fabricated device exhibited a low turn-on voltage of 13 V and an emission anode current of 3.6 muA/tip at V-AC = 50 V and V-GC = open. After high field activation treatment, the turn-on voltage was reduced to 2 V and the emission anode current was increased to 9 muA/tip at the same bias condition. With changing gate bias, the emission current showed three different I-V characteristics; a negative resistance region with large transconductance of 200 muS/50 triodes, a positive. resistance region with relatively small transconductance, and a, zero transconductance region. (C) 2003 American Vacuum Society.