Interstrip Capacitance ATLAS nn 80AC

Author: Riko Wichmann
This page was created February 7, 1997, last modified February 7, 1997

We measured the interstrip capacitance and the strip resistance of the ATLAS nn 80 AC prototype detectors. The interstrip capacitance was measured between 1 strip and its 5 neighbors on each side. The detector has 6 separate regions which are different in metal width and/or p-stop type:

Region	Metal width [µm]	p-stop type	strip R [ohm]	C_inter [pF/6cm]
1	16	slit common	66	5.8
2	16	individual	65	5.9
3	16	combined	66	5.6
4	16	full common	65	6.8
5	22	full common	49	7.7
6	10	full common	104	6.3

CV curves

capacitance separation between next and further neighbors
region 1
region 2
region 3
region 4
region 5
region 6

Conclusion (by H.F.-W. Sadrozinski)

Full common has larger capacitance by 15-20%. We discussed at CERN that the impedance of the p-frame is NOT infinite but that it is a few % of 1/(omega*C). So one should expect signal/noise propagation through it.
Combined looks slightly better, as noise seem to show, but maybe not worth the design effort/complication
Individual looks good
Metal resistance very, very good and scaling reliably with metal width.
Capacitance mainly given by widest structure (either implant or metal), but metal width plays small role (region 6 vs 4)

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