  Trapped ions are pre-eminent candidates for building quantum information
processors and quantum simulators. They have been used to demonstrate quantum
gates and algorithms, quantum error correction, and basic quantum simulations.
However, to realise the full potential of such systems and make scalable
trapped-ion quantum computing a reality, there exist a number of practical
problems which must be solved. These include tackling the observed high
ion-heating rates and creating scalable trap structures which can be simply and
reliably produced. Here, we report on cryogenically operated silicon ion traps
which can be rapidly and easily fabricated using standard semiconductor
technologies. Single $^{40}$Ca$^+$ ions have been trapped and used to
characterize the trap operation. Long ion lifetimes were observed with the
traps exhibiting heating rates as low as $\dot{\bar{n}}=$ 0.33 phonons/s at an
ion-electrode distance of 230 $\mu$m. These results open many new avenues to
arrays of micro-fabricated ion traps.
