  We report the design, fabrication, and characterization of a microfabricated
surface-electrode ion trap that supports controlled transport through the
two-dimensional intersection of linear trapping zones arranged in a
ninety-degree cross. The trap is fabricated with
very-large-scalable-integration (VLSI) techniques which are compatible with
scaling to a larger quantum information processor. The shape of the
radio-frequency (RF) electrodes is optimized with a genetic algorithm to
minimize axial pseudopotential barriers and to minimize ion heating during
transport. Seventy-eight independent DC control electrodes enable fine control
of the trapping potentials. We demonstrate reliable ion transport between
junction legs, trapping of ion chains with nearly-equal spacing in one of the
trap's linear sections, and merging and splitting ions from these chains.
Doppler-cooled ions survive more than 10^5 round-trip transits between junction
legs without loss and more than sixty-five consecutive round trips without
laser cooling.
