Title :
On the thermal stability of atomic layer deposited TiN as gate electrode in MOS devices
Author :
Westlinder, J. ; Schram, T. ; Pantisano, L. ; Cartier, E. ; Kerber, A. ; Lujan, G.S. ; Olsson, J. ; Groeseneken, G.
Author_Institution :
Mater. Sci. Dept., Uppsala Univ., Sweden
Abstract :
The work function of ALD TiN was found to be above 5 eV after RTP annealing below 800/spl deg/C in a nitrogen atmosphere, while higher annealing temperatures cause a drop in work function by about 0.3-0.5 eV. The effect was found for TiN metal gates on both SiO/sub 2/ and Al/sub 2/O/sub 3/ gate dielectrics in MOS-capacitors and was seen in C-V as well as in I-V measurements. On the contrary, annealing of SiO/sub 2/ capacitors in oxygen-enriched N/sub 2/ atmosphere increased the work function. A variation in EOT of less than 2 A was demonstrated for the various annealing temperatures, concluding that the ALD TiN is stable in contact with the different dielectric materials. However, the decrease in work function that is found in this investigation may implicate that ALD TiN is less suitable as a metal gate for pMOSFETs.
Keywords :
CMOS integrated circuits; MOS capacitors; MOSFET; alumina; integrated circuit metallisation; nitrogen; rapid thermal annealing; semiconductor device metallisation; silicon compounds; thermal stability; titanium compounds; work function; 5 eV; 800 C; ALD TiN; Al/sub 2/O/sub 3/ gate dielectric; C-V measurements; I-V measurements; MOS capacitors; MOS devices; N/sub 2/; RTA; SiO/sub 2/ gate dielectric; TiN gate electrode; TiN-Al/sub 2/O/sub 3/; TiN-SiO/sub 2/; annealing temperatures; atomic layer deposited TiN; nitrogen atmosphere; pMOSFETs; thermal stability; work function; Annealing; Atmosphere; Atomic layer deposition; Dielectrics; Electrodes; MOS devices; Nitrogen; Temperature; Thermal stability; Tin;
Journal_Title :
Electron Device Letters, IEEE
DOI :
10.1109/LED.2003.816579
