University of Virginia

Center for Nanoscopic Materials Design

University of Virginia MRSECNanoscale Control of GeSi/Si Quantum Dot Nucleation by In-Situ FIB Surface Modification

A. Portavoce, M. Kammler, R. Hull, UVa; F. Ross, M. Reuter, R. Tromp, IBM

QCA Bistable Logic QCA Adder Circuit Ex-Situ AFM ImageIn-Situ TEM Images: Left : FIB implanted Right: Ge QD Nucleation

UHV-CVD-TEM-FIB (IBM)

Typical Ga+ Dose: 1014 cm-2

University of Virginia

Center for Nanoscopic Materials Design

• Intrinsic Merit– Fundamental advances in understanding epitaxial nucleation on

locally modified surfaces– Detailed understanding of FIB-guided nucleation: local strain plus

surface nano-topography– Scaleable to large arrays – FIB write speed c. 104 features per

second– Extraploation to new systems e.g. epitaxial metallic oxide dots (J.

Groves, Y. Du, UVa)• Broader Impact

– Possible application to Quantum Cellular Automata and other Nanoelectronic Architectures (with G. Snider, X. Luo, Notre Dame)

– Close collaboration between leading industrial research lab (IBM Yorktown Heights) and UVa MRSEC

– Integration of Research and Education: new course at UVa – MSE 791, Nanoscale Processes at Surfaces

• Next Steps– Smaller QD spacings (reduce instrumental vibration, smaller ion

spot sizes)– Developing mass-selecting FIB column: Si, Ge, As. B beams from

mass separated alloy sources– In-situ LEEM, STM studies