Ion beam induced current (IBIC) analysis allows to study the effects of various materials selection to the detector performance. We analysed Cadmium Telluride (CdTe) pad detectors which were passivated either by using aluminium nitride (AlN) or by aluminium oxide (Al 2 O 3 ). By using microbeam with 2 MeV protons, we were able to measure various surface effects, the charge collection efficiency, and analyse the impact of surface defects which could reduce the detector performance in applications such as medical imaging. The detectors we measured had surface area of 1 cm × 1 cm, and thickness of 1 mm. Various bias settings were applied to allow detailed charge collection studies. In this paper we show some selected results of the IBIC measurements.