Nanowire-metal heterostructures for high performance MOSFETs

SummaryIn this work we report on the formation, of copper-germanide/germanium nanowire (NW) heterostructures with atomically sharp interfaces. The copper-germanide (Cu3Ge) formation process is enabled by a chemical reaction between metallic Cu pads and vapor-liquid-solid (VLS) grown Ge-NWs. The atomic scale aligned formation of the Cu3Ge segments is controlled by in situ SEM monitoring at 310 °C thereby enabling length control of the intrinsic Ge-NW down to a few nm. The single crystal Cu3Ge/Ge/Cu3Ge heterostructures were used to fabricate Ω-gated Ge-NW field effect transistors with Schottky Cu3Ge source/drain contacts. Temperature dependent I/V measurements revealed the metallic properties of the Cu3Ge contacts with a maximum current carrier density of 5 × 107 A/cm2. Prior to the gate deposition the intrinsic Ge-NW was modified with a focussed Ga+ ion beam. According to the thermoionic emission theory we determined an effective Schottky barrier height reduction from 218 meV to about 115 meV due to Ga+ implantation.

[1]  Andrew L. Schmitt,et al.  Ultralong single-crystal metallic Ni2Si nanowires with low resistivity. , 2007, Nano letters.

[2]  Yoshihiko Kanemitsu,et al.  Visible photoluminescence of Ge microcrystals embedded in SiO2 glassy matrices , 1991 .

[3]  Paolo Lugli,et al.  Silicon-nanowire transistors with intruded nickel-silicide contacts. , 2006, Nano letters.

[4]  Charles M. Lieber,et al.  Doping and Electrical Transport in Silicon Nanowires , 2000 .

[5]  J. Fischer,et al.  Disorder effects in focused-ion-beam-deposited Pt contacts on GaN nanowires. , 2005, Nano letters.

[6]  H. M. Tawancy,et al.  Effect of phase transitions in copper-germanium thin film alloys on their electrical resistivity , 1995 .

[7]  Charles M. Lieber,et al.  Logic Gates and Computation from Assembled Nanowire Building Blocks , 2001, Science.

[8]  S. Delage,et al.  Output power density of 5.1/mm at 18 GHz with an AlGaN/GaN HEMT on Si substrate , 2006, IEEE Electron Device Letters.

[9]  S. M. Sze,et al.  Physics of semiconductor devices , 1969 .

[10]  Charles M Lieber,et al.  Lasing in single cadmium sulfide nanowire optical cavities. , 2005, Nano letters.

[11]  Keiichi Yamamoto,et al.  Fabrication of iron silicide nanowires from nanowire templates , 2006 .

[12]  Charles M. Lieber,et al.  Nonvolatile Memory and Programmable Logic from Molecule-Gated Nanowires , 2002 .

[13]  Charles M. Lieber,et al.  GaN nanowire lasers with low lasing thresholds , 2005 .

[14]  L. Samuelson,et al.  Infrared photodetectors in heterostructure nanowires. , 2006, Nano letters.

[15]  Yu Huang,et al.  Indium phosphide nanowires as building blocks for nanoscale electronic and optoelectronic devices , 2001, Nature.

[16]  Wei Lu,et al.  Single-crystal metallic nanowires and metal/semiconductor nanowire heterostructures , 2004, Nature.

[17]  C. Detavernier,et al.  Thin film reaction of transition metals with germanium , 2006 .

[18]  M. B. Prince,et al.  Drift Mobilities in Semiconductors. I. Germanium , 1953 .

[19]  Charles M. Lieber,et al.  Functional nanoscale electronic devices assembled using silicon nanowire building blocks. , 2001, Science.

[20]  J. Woo,et al.  Characterization of copper germanide as contact metal for advanced MOSFETs , 2006, IEEE Electron Device Letters.

[21]  L. Krusin-Elbaum,et al.  UNUSUALLY LOW RESISTIVITY OF COPPER GERMANIDE THIN FILMS FORMED AT LOW TEMPERATURES , 1991 .

[22]  G.E. Moore,et al.  Cramming More Components Onto Integrated Circuits , 1998, Proceedings of the IEEE.

[23]  Charles M Lieber,et al.  One-dimensional hole gas in germanium/silicon nanowire heterostructures. , 2005, Proceedings of the National Academy of Sciences of the United States of America.

[24]  Yu Huang,et al.  Single crystalline PtSi nanowires, PtSi/Si/PtSi nanowire heterostructures, and nanodevices. , 2008, Nano letters.

[25]  Charles M. Lieber,et al.  Ge/Si nanowire heterostructures as high-performance field-effect transistors , 2006, Nature.