Nn. Chubun et al., Fabrication and characterization of singly addressable arrays of polysilicon field-emission cathodes, SOL ST ELEC, 45(6), 2001, pp. 1003-1007
Polysilicon is a viable candidate material for field-emission microelectron
ics devices. It can be competitive for large size, cost-sensitive applicati
ons such as flat-panel displays and micro electro-mechanical systems. Singl
y addressable arrays of field-emission cells were fabricated in a matrix co
nfiguration using a subtractive process on polysilicon-on-insulator substra
tes. Matrix rows were fabricated as insulated polycrystalline silicon strip
es with sharp emission tips; and matrix columns were deposited as gold thin
film electrodes with round gate openings. Ion implantation has been used t
o provide the required conductivity of the polysilicon layer. To reduce rad
ius of curvature of the polysilicon tips, an oxidation sharpening process w
as used. The final device had polysilicon emission tips with end radii smal
ler than 15 nm, surrounded by gate apertures of 0.4 tm in diameter. Field e
mission properties of the cathodes were measured at a pressure of about 10(
-8) Torr, to emulate vacuum conditions available in sealed vacuum microelec
tronics devices. It was found that an emission current of I nA appears at a
gate voltage of 25 V and can be increased up to I VA at 70 V. Over this ra
nge of current, no "semiconductor" deviation from the Fowler-Nordheim equat
ion was observed. I-V characteristics measured in cells of a 10 x 10 matrix
, with a cell spacing of 50 pm demonstrated reasonable uniformity and repro
ducibility. (C) 2001 Elsevier Science Ltd. All rights reserved.