Technology development of 3-D GaAs radiation detectors

A novel type of GaAs radiation detector featuring a three-dimensional array of electrodes that penetrate through the detector bulk and the fabrication technology required are described. Using a pulsed Nd: YAG laser we have obtained repeatable round holes of 30 μm diameter with little or no taper and smooth internal walls. With a pulsed Ti: Sapphire laser we have obtained repeatable holes of 100 μm diameter with coarse internal walls. Drilling damage to the substrate is discussed along with possible prevention steps and post-drilling treatment.