J.M. Hergenrother,
G.D. Wilk,
T. Nigam,
F.P. Klemens,
D. Monroe,
P.J. Silverman,
T.W. Sorsch,
B. Busch,
M.L. Green,
M.R. Baker, [......],
K. Short,
K. Steiner,
D.A. Muller,
P.M. Voyles,
J.L. Grazul,
E. Shero,
M.E. Givens, C. Pomarede,
M. Mazanec,
C. Werkhoven
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ABSTRACT: We have integrated HfO<sub>2</sub> and Al<sub>2</sub>O<sub>3</sub>
gate dielectrics grown by atomic layer chemical vapor deposition (ALD)
with poly-Si gate electrodes in the vertical replacement-gate (VRG)
MOSFET geometry. These transistors are among the first reported with ALD
HfO<sub>2</sub> gate dielectrics, and have HfO<sub>2</sub> target
equivalent oxide thicknesses (tEOT's) down to 13 Å. The
poly-crystalline HfO<sub>2</sub> films in these VRG nMOSFETs exhibit
extremely low gate leakage (GL) current densities of J<sub>G</sub> ~ 10
<sup>-7</sup> A/cm<sup>2</sup> at V<sub>G</sub>-V<sub>T,Long</sub> = 0.6
V for 15 Å tEOT devices. This indicates that amorphous gate
dielectrics may not be necessary to meet GL requirements.
HfO<sub>2</sub> devices with 50 nm gate length L<sub>G</sub> exhibit
drive currents [normalized by the coded width W<sub>C</sub>] of 490
μA/μm for 1 V operation (overdrive V<sub>GS</sub>-V<sub>T</sub> =
0.6 V) with good short-channel performance. These results demonstrate
that ALD is compatible with the demanding VRG geometry, thereby
illustrating that it should be well-suited to essentially any novel
device structure built with Si-compatible materials
Electron Devices Meeting, 2001. IEDM Technical Digest. International; 02/2001