1. Alumina Oxide Treatment Effect on Bias Resistance BZ1 W277 P19 Untreated (Grounds Tied) BZ1 W230 P7 Alumina Treated (Grounds Not Tied) Bias Voltage (V) Average Rbias (Ohms) 54.31E+10 502.81E+10 1002.99E+10 1503.67E+10 2009.83E+10 2502.34E+10 Bias Voltage (V)Rbias (Ohms) 52.31E+04 507.81E+04 1005.00E+05 1501.12E+06 2001.12E+06 2501.13E+06

2. Tests were done by holding 3 neighboring strips at a varied potential and observing the current on the center strip while biasing the detecting via its backplane. For the untreated device, Rbias was equal to the inverse of the slope of the line fit to the data of the voltage and center strip’s current. For the treated device, no linear relationship was found, so Rbias was calculated between each strip voltage step and then averaging all values for each biasing voltage.

3. Measuring Bias Resistance

5. Circuit Used to Measure Bias Resistance All 3 strips on the DC pads were held at the same potential. Ground of the power supply should be connected to grounds of the parameter analyzer.

7. Difference in Interstrip Resistance Calculated Based on Probe Configurations Bias Voltage (V) Rint (Ohms), Center Strip Held at Ground Rint (Ohms), Neighboring Strips Held at Ground (Ignoring Rbias term) 54.47E+082.49E+08 505.25E+085.56E+08 1005.38E+084.08E+08 1504.99E+085.33E+08 2004.56E+084.94E+08 2504.27E+084.56E+08

8. W230 P7 Post Alumina Treatment Rint, small difference in calculation based on probe configurations (not accounting for bias resistance)

9. Circuit Used to Measure Interstrip Resistance The different probe configurations are: 1. Center strip held at ground, its neighbors held at varying potentials. 2. Center strip held at varying potential, its neighbors held at ground. In both cases, the 3 probes are connected to The parameter analyzer.

10. Interstrip Resistance Calculation Center strip held at ground, varying potential applied to neighboring strips: dI Center /dV Center =2/R Interstrip Neighboring strips held at ground, varying potential applied to center strip: dI Center /dV Center = (-2/R Interstrip )-(1/R Bias )

11. Leakage current of the detector suddenly increased and stayed higher, 25uA at 312V

12. W230 P7 Post Alumina Treatment Bias Resistors

13. W281 P7 Bias Resistors Post Alumina Treatment

14. W278 P7 Bias Resistors Post Alumina Treatment

15. Untreated BZ1 Bias Resistors

16. Strip numbers missing only on W278 P7 after alumina treatment