Radiation detectors and methods of fabricating radiation detectors

A method for fabricating a radiation detector, the method comprising:

• mechanically polishing at least a first surface of a semiconductor wafer using a polishing sequence including a plurality of polishing steps, wherein a last polishing step of the polishing sequence includes polishing with a slurry having a grain size smaller than about 0.1 μm to create a polished first surface;
• applying (i) an encapsulation layer on a top of the polished first surface to seal the polished first surface and (ii) a photoresist layer on top of the encapsulation layer on the polished first surface;
• creating openings in the photoresist layer;
• partially etching the encapsulation layer via the openings in the photoresist layer to partially remove the encapsulation layer and creating undercuts of the encapsulation layer under the photoresist layer;
• partially etching the polished first surface of the semiconductor wafer via the openings in the photoresist layer and in the encapsulation layer to partially etch the semiconductor wafer creating etched regions, in the first surface, having undercuts of the semiconductor wafer under the encapsulation layer to produce non-etched gap regions between the etched regions of the polished first surface;
• etching a second surface of the semiconductor wafer;
• applying pixelated anode electrodes in the etched regions of the polished first surface and a monolithic cathode electrode on a second surface of the semiconductor wafer;
• and
• removing the photoresist layer by a liftoff process.