A variable-energy focused ion-beam system for in situ microfabrication
Since the development of the liquid-metal ion source (LMIS) in the mid 1970's, dramatic progress has been achieved in formation of high-intensity focused ion beams (FIBs). While the LMIS has many desirable qualities, the threshold voltage for ion emission (typically 7-10 kV) sets the absolute lower limit to the beam-acceleration voltage in conventional electrostatic FIB systems. The design, fabrication, and experimental characterization of a variable-energy FIB systems are described. The design employs an immersion lens in the retarding-field mode to achieve a final landing energy continuously variable over the range of 0-50 keV. This configuration allows both low- and high-energy operation despite the emission threshold constraint imposed by the LMIS, and also minimizes chromatic aberration at low landing energies. A Monte Carlo program was developed that allows simulation of stochastic space-charge effects and a prediction of performance limits imposed by space-charge-induced beam broadening. The ultimate goal is to combine an in-situ FIB capability with molecular beam epitaxial growth of GaAs for fabrication of advanced electronic and optoelectronic devices.
- Research Organization:
- Stanford Univ., CA (USA)
- OSTI ID:
- 5168916
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
430200* -- Particle Accelerators-- Beam Dynamics
Field Calculations
& Ion Optics
ARSENIC COMPOUNDS
ARSENIDES
BEAM DYNAMICS
BEAMS
ELECTRONIC EQUIPMENT
EPITAXY
EQUIPMENT
FABRICATION
FOCUSING
GALLIUM ARSENIDES
GALLIUM COMPOUNDS
ION BEAMS
MOLECULAR BEAM EPITAXY
MONTE CARLO METHOD
PNICTIDES
SEMICONDUCTOR DEVICES
SIMULATION
SPACE CHARGE