Mr Vladislav Marochkin (Pixpolar / Lappeenranta Univ. of Technology (FI))
The Silicon Drift Detectors (SDDs) have replaced simple diodes in demanding X-ray fluorescence applications like in element analyzers capable of detecting light elements. The reason for this is that with similar collection area the SDD’s have a much smaller output capacitance due to a much smaller anode size and thus much better Signal to Noise Ratio (SNR) at small signal levels than diodes. This is achieved by placing around a miniature sized anode rings that are biased such that inside the SDD’s fully depleted bulk a horizontal electric field component is established guiding signal charges towards the anode. A typical problem still present in SDDs is interface generated dark noise, which is caused when leakage current generated at depleted interfaces mixes with the signal charge. It has been shown previously that it is possible to prevent the formation of interface generated dark noise in SDDs, for example by implementing at SDD’s interface “electron rivers” as demonstrated by W. Chen at al. But the realization of such SDDs has been rather complicated. We present an advanced SDD design comprising a novel ring arrangement preventing the formation of interface generated dark noise and enabling simple manufacturing with standard process steps. In this work the design and operation principle of the proposed SDD are presented. The operation of the proposed SDD has been evaluated on TCAD with 2D process and device simulations. The simulation results demonstrate the viability of the design and the operation principle of the proposed novel SDD design as well as the absence of interface generated dark noise. Key words: silicon drift detector, SDD, device simulation, interface generated dark noise, interface leakage current.
Mr Artto Aurola (Pixpolar / Lappeenranta Univ. of Technology (FI)) Mr Vladislav Marochkin (Pixpolar / Lappeenranta Univ. of Technology (FI))
Mrs Maria Golovleva (Lappeenranta Univ. of Technology (FI)) Tuure Tuuva (Lappeenranta Univ. of Technology (FI))