Study of the correlation between the cutting edge current breakdown and the simulated lateral electrical field boundary in high resistivity silicon detectors with multi-guard ring structure
Z. Li et al., Study of the correlation between the cutting edge current breakdown and the simulated lateral electrical field boundary in high resistivity silicon detectors with multi-guard ring structure, IEEE NUCL S, 47(3), 2000, pp. 729-736
High resistivity silicon detectors with Multi-Guard Ring Structure (MGRS),
after being subjected to laser cutting to various distances (L, from 10 mu
m to 1000 mu m) from the outer most guard ring, have been used to investiga
te the effect of cutting edge current breakdown (CECB). The bias on the out
er most guard ring at which CECB starts, or the edge breakdown voltage V-b,
increases monotonically with L. This result has been compared to the simul
ated lateral depletion depth (W-L) from the outer most guard ring as a func
tion of bias voltage V with very good correlation. For a given bias V, CECB
occurs if W-L is larger than L, suggesting that current injects as soon as
electrical field reaches the cutting edge. These results indicate that dam
age caused by laser cutting is very much localized to the edge itself (with
in a few mu ms). The edge breakdown current can be separated from the bulk
leakage current by grounding one of the guard rings. The advantage of using
MGRS to spread the electrical potential over a large distance to prevent p
ossible high field breakdown was also simulated and discussed.