Nanometer-scale lithography on Si(001) using adsorbed H as an atomic layer resist
- Sandia National Laboratories, Albuquerque, New Mexico 87185-1413 (United States)
We describe nanometer-scale feature definition in adsorbed hydrogen layers on Si(001) surfaces by exposure to low energy electrons from a scanning tunneling microscope tip. Feature sizes range from {lt}5 to {approx_gt}40 nm as a function of bias voltage (5{endash}30 V) and exposure dose (1{endash}10{sup 4} {mu}C/cm). We show that the cross section for electron stimulated desorption of hydrogen has a threshold at 6{endash}8 eV and is nearly constant from 10 to 30 eV, so that above threshold the feature profiles are a direct reflection of the electron flux profile at the surface. Radial flux distributions are best fit by a simple exponential function, where the decay length is dependent primarily on the tip{endash}sample separation. Low intensity tails at large radius are also observed for high bias emission. Comparison to field emission simulations shows that our tip has an {open_quote}{open_quote}effective radius{close_quote}{close_quote} of approximately 30 nm. Simulations demonstrate that tip geometry and tip{endash}sample separation play the dominant role in defining the electron flux distribution, and that optimum beam diameter at the sample is obtained at small tip{endash}sample separation (low bias) with sharp tips. We show that adsorbed hydrogen is a robust resist that can be used as a mask for selective area deposition of metals by chemical vapor deposition. Fe lines 10 nm wide are deposited by pyrolysis of Fe(CO){sub 5} in areas where H has been desorbed, with minimal nucleation in the H-passivated areas. {copyright} {ital 1996 American Vacuum Society}
- Research Organization:
- Sandia National Laboratories (SNL), Albuquerque, NM, and Livermore, CA (United States)
- DOE Contract Number:
- AC04-94AL85000
- OSTI ID:
- 285557
- Journal Information:
- Journal of Vacuum Science and Technology. B, Microelectronics Processing and Phenomena, Vol. 14, Issue 3; Other Information: PBD: May 1996
- Country of Publication:
- United States
- Language:
- English
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