Title :
Fully self-aligned tri-layer a-Si:H thin-film transistors with deposited doped contact layer
Author :
Thomasson, D.B. ; Jackson, T.N.
Author_Institution :
Dept. of Electr. Eng., Pennsylvania State Univ., University Park, PA, USA
fDate :
4/1/1998 12:00:00 AM
Abstract :
We demonstrate a new self-aligned TFT process for hydrogenated amorphous silicon thin-film transistors (a-Si:H TFTs). Two backside exposure photolithography steps are used to fabricate fully self-aligned tri-layer TFTs with deposited n/sup +/ contacts. Since no critical data alignment is required, this simple process is well suited to fabrication of short channel TFTs. We have fabricated fully self-aligned tri-layer a-Si:H TFTs with excellent device performance, and contact overlaps <1 μm. For a 20-μm channel length TFT with an a-Si:H thickness of 13 nm, the linear region (V/sub DS/=0.1 V) and saturation region (V/sub DS/=25 V) extrinsic mobility values are both 1.2 cm2/V-s, the off currents are <1 pA, and the on/off current ratio is >10/sup 7/.
Keywords :
amorphous semiconductors; carrier mobility; elemental semiconductors; hydrogen; photolithography; semiconductor device metallisation; silicon; thin film transistors; 0.1 V; 13 nm; 20 micron; 25 V; Si:H; backside exposure photolithography steps; contact overlaps; deposited doped contact layer; extrinsic mobility values; fully self-aligned tri-layer TFTs; linear region; off currents; on/off current ratio; saturation region; short channel TFT; Active matrix liquid crystal displays; Amorphous silicon; Doping; Etching; Fabrication; Lithography; Manufacturing processes; Parasitic capacitance; Semiconductor films; Thin film transistors;
Journal_Title :
Electron Device Letters, IEEE
