  In order to study interactions of atomic ions with ultracold neutral atoms,
it is important to have sub-$\mu$m control over positioning ion crystals.
Serving for this purpose, we introduce a microfabricated planar ion trap
featuring 21 DC electrodes. The ion trap is controlled by a home-made FPGA
voltage source providing independently variable voltages to each of the DC
electrodes. To assure stable positioning of ion crystals with respect to
trapped neutral atoms, we integrate into the overall design a compact mirror
magneto optical chip trap (mMOT) for cooling and confining neutral $^{87}$Rb
atoms. The trapped atoms will be transferred into an also integrated chipbased
Ioffe-Pritchard trap potential formed by a Z-shaped wire and an external bias
magnetic field.We introduce the hybrid atom-ion chip, the microfabricated
planar ion trap and use trapped ion crystals to determine ion lifetimes, trap
frequencies, positioning ions and the accuracy of the compensation of
micromotion.
