Reverse biasing and breakdown behavior of PureB diodes

In this paper, the reverse biasing and breakdown properties of the PureB diodes are investigated for different methods of processing the PureB anode window and the metal contacting. In particular, micron-sized devices are examined in order to assess their suitability for use in dense imaging arrays that may require operation as avalanche photodiodes to obtain the necessary photosensitivity [6]. For such small devices implanted guard rings cannot be implemented without paying a penalty in fill-factor. At the same time it is also desirable to position the photosensitive area away from the oxide perimeter where permanent damage can be inflicted by high reverse currents. Therefore, a “virtual” guard, using an n-enhancement implantation in the central region of the diode is applied here.