Details
| Original language | English |
|---|---|
| Title of host publication | CMOS Gate-Stack Scaling - Materials, Interfaces and Reliability Implications |
| Publisher | Materials Research Society |
| Pages | 97-108 |
| Number of pages | 12 |
| ISBN (print) | 9781605111285 |
| Publication status | Published - 17 Aug 2009 |
| Event | 2009 MRS Spring Meeting - San Francisco, CA, United States Duration: 14 Apr 2009 → 16 Apr 2009 |
Publication series
| Name | Materials Research Society Symposium Proceedings |
|---|---|
| Volume | 1155 |
| ISSN (Print) | 0272-9172 |
Abstract
Many materials systems are currently under consideration as potential replacements for SiO2 as the gate dielectric material for sub-0.1 μm CMOS technology. We present results for crystalline gadolinium oxides on silicon in the cubic bixbyite structure grown by solid source molecular beam epitaxy. On Si(100), crystalline Gd2O3 grows usually as (110)-oriented domains, with two orthogonal in-plane orientations. Layers grown under best vacuum conditions often exhibit poor dielectric properties due to the formation of crystalline interfacial silicide inclusions. Additional oxygen supply during growth improves the dielectric properties significantly. Layers grown by an optimized MBE process display a sufficiently high-K value to achieve equivalent oxide thickness values < 1 nm, combined with ultra-low leakage current densities, good reliability, and high electrical breakdown voltage. A variety of MOS capacitors and field effect transistors has been fabricated based on these layers. Efficient manipulation of Si(100) 4° miscut substrate surfaces can lead to single domain epitaxial Gd2O3 layer. Such epi-Gd2O3 layers exhibited significant lower leakage currents compared to the commonly obtained epitaxial layers with two orthogonal domains. For capacitance equivalent thicknesses below 1 nm, this differences disappear, indicating that for ultrathin layers direct tunneling becomes dominating. We investigated the effect of post-growth annealings on layer properties. We showed that a standard forming gas anneal can eliminate flatband instabilities and hysteresis as well as reduce leakage currents by saturating dangling bond caused by the bonding mismatch. In addition, we investigated the impact of rapid thermal anneals on structural and electrical properties of crystalline Gd2O3 layers grown on Si with different orientations. The degradation of layers can be significantly reduced by sealing the layer with amorphous silicon prior to annealing.
ASJC Scopus subject areas
- Materials Science(all)
- General Materials Science
- Physics and Astronomy(all)
- Condensed Matter Physics
- Engineering(all)
- Mechanics of Materials
- Engineering(all)
- Mechanical Engineering
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CMOS Gate-Stack Scaling - Materials, Interfaces and Reliability Implications. Materials Research Society, 2009. p. 97-108 (Materials Research Society Symposium Proceedings; Vol. 1155).
Research output: Chapter in book/report/conference proceeding › Conference contribution › Research › peer review
}
TY - GEN
T1 - Epitaxial Lanthanide Oxide based Gate Dielectrics
AU - Osten, H. Jörg
AU - Laha, Apurba
AU - Fissel, Andreas
PY - 2009/8/17
Y1 - 2009/8/17
N2 - Many materials systems are currently under consideration as potential replacements for SiO2 as the gate dielectric material for sub-0.1 μm CMOS technology. We present results for crystalline gadolinium oxides on silicon in the cubic bixbyite structure grown by solid source molecular beam epitaxy. On Si(100), crystalline Gd2O3 grows usually as (110)-oriented domains, with two orthogonal in-plane orientations. Layers grown under best vacuum conditions often exhibit poor dielectric properties due to the formation of crystalline interfacial silicide inclusions. Additional oxygen supply during growth improves the dielectric properties significantly. Layers grown by an optimized MBE process display a sufficiently high-K value to achieve equivalent oxide thickness values < 1 nm, combined with ultra-low leakage current densities, good reliability, and high electrical breakdown voltage. A variety of MOS capacitors and field effect transistors has been fabricated based on these layers. Efficient manipulation of Si(100) 4° miscut substrate surfaces can lead to single domain epitaxial Gd2O3 layer. Such epi-Gd2O3 layers exhibited significant lower leakage currents compared to the commonly obtained epitaxial layers with two orthogonal domains. For capacitance equivalent thicknesses below 1 nm, this differences disappear, indicating that for ultrathin layers direct tunneling becomes dominating. We investigated the effect of post-growth annealings on layer properties. We showed that a standard forming gas anneal can eliminate flatband instabilities and hysteresis as well as reduce leakage currents by saturating dangling bond caused by the bonding mismatch. In addition, we investigated the impact of rapid thermal anneals on structural and electrical properties of crystalline Gd2O3 layers grown on Si with different orientations. The degradation of layers can be significantly reduced by sealing the layer with amorphous silicon prior to annealing.
AB - Many materials systems are currently under consideration as potential replacements for SiO2 as the gate dielectric material for sub-0.1 μm CMOS technology. We present results for crystalline gadolinium oxides on silicon in the cubic bixbyite structure grown by solid source molecular beam epitaxy. On Si(100), crystalline Gd2O3 grows usually as (110)-oriented domains, with two orthogonal in-plane orientations. Layers grown under best vacuum conditions often exhibit poor dielectric properties due to the formation of crystalline interfacial silicide inclusions. Additional oxygen supply during growth improves the dielectric properties significantly. Layers grown by an optimized MBE process display a sufficiently high-K value to achieve equivalent oxide thickness values < 1 nm, combined with ultra-low leakage current densities, good reliability, and high electrical breakdown voltage. A variety of MOS capacitors and field effect transistors has been fabricated based on these layers. Efficient manipulation of Si(100) 4° miscut substrate surfaces can lead to single domain epitaxial Gd2O3 layer. Such epi-Gd2O3 layers exhibited significant lower leakage currents compared to the commonly obtained epitaxial layers with two orthogonal domains. For capacitance equivalent thicknesses below 1 nm, this differences disappear, indicating that for ultrathin layers direct tunneling becomes dominating. We investigated the effect of post-growth annealings on layer properties. We showed that a standard forming gas anneal can eliminate flatband instabilities and hysteresis as well as reduce leakage currents by saturating dangling bond caused by the bonding mismatch. In addition, we investigated the impact of rapid thermal anneals on structural and electrical properties of crystalline Gd2O3 layers grown on Si with different orientations. The degradation of layers can be significantly reduced by sealing the layer with amorphous silicon prior to annealing.
UR - http://www.scopus.com/inward/record.url?scp=77950993827&partnerID=8YFLogxK
U2 - 10.1557/proc-1155-c01-01
DO - 10.1557/proc-1155-c01-01
M3 - Conference contribution
AN - SCOPUS:77950993827
SN - 9781605111285
T3 - Materials Research Society Symposium Proceedings
SP - 97
EP - 108
BT - CMOS Gate-Stack Scaling - Materials, Interfaces and Reliability Implications
PB - Materials Research Society
T2 - 2009 MRS Spring Meeting
Y2 - 14 April 2009 through 16 April 2009
ER -