Low temperature thermal ALD of a SiNxinterfacial diffusion barrier and interface passivation layer on SixGe1- x(001) and SixGe1- x(110).
Atomic layer deposition of a silicon rich SiNxlayer on Si0.7Ge0.3(001), Si0.5Ge0.5(001), and Si0.5Ge0.5(110) surfaces has been achieved by sequential pulsing of Si2Cl6and N2H4precursors at a substrate temperature of 285 °C. XPS spectra show a higher binding energy shoulder peak on Si 2p indicative of SiOxNyClzbonding while Ge 2p and Ge 3d peaks show only a small amount of higher binding energy components consistent with only interfacial bonds, indicating the growth of SiOxNyon the SiGe surface with negligible subsurface reactions. Scanning tunneling spectroscopy measurements confirm that the SiNxinterfacial layer forms an electrically passive surface on p-type Si0.70Ge0.30(001), Si0.50Ge0.50(110), and Si0.50Ge0.50(001) substrates as the surface Fermi level is unpinned and the electronic structure is free of states in the band gap. DFT calculations show that a Si rich a-SiO0.4N0,4interlayer can produce lower interfacial defect density than stoichiometric a-SiO0.8N0.8, substoichiometric a-Si3N2, or stoichiometric a-Si3N4interlayers by minimizing strain and bond breaking in the SiGe by the interlayer. Metal-oxide-semiconductor capacitors devices were fabricated on p-type Si0.7Ge0.3(001) and Si0.5Ge0.5(001) substrates with and without the insertion of an ALD SiOxNyinterfacial layer, and the SiOxNylayer resulted in a decrease in interface state density near midgap with a comparable Cmaxvalue.
Materials Science and Engineering Program, University of California, San Diego, La Jolla, California 92093, USA.
Mary
M
Edmonds
Materials Science and Engineering Program, University of California, San Diego, La Jolla, California 92093, USA.
Kasra
K
Sardashti
Materials Science and Engineering Program, University of California, San Diego, La Jolla, California 92093, USA.
Steven
S
Wolf
Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California 92093, USA.
Evgueni
E
Chagarov
Department of Electrical and Computer Engineering, University of California, San Diego, La Jolla, California 92093, USA.
Max
M
Clemons
Materials Science and Engineering Program, University of California, San Diego, La Jolla, California 92093, USA.
Tyler
T
Kent
Materials Science and Engineering Program, University of California, San Diego, La Jolla, California 92093, USA.
Jun Hong
JH
Park
Department of Materials Science and Engineering, Stanford University, Stanford, California 94305, USA.
Kechao
K
Tang
Department of Materials Science and Engineering, Stanford University, Stanford, California 94305, USA.
Paul C
PC
McIntyre
Applied Materials, Sunnyvale, California 94085, USA.
Naomi
N
Yoshida
Applied Materials, Sunnyvale, California 94085, USA.
Lin
L
Dong
Rasirc, Inc., San Diego, California 92126, USA.
Russell
R
Holmes
Rasirc, Inc., San Diego, California 92126, USA.
Daniel
D
Alvarez
Materials Science and Engineering Program, University of California, San Diego, La Jolla, California 92093, USA.
Andrew C
AC
Kummel