1. Daniela Bortoletto, Amitava Roy, Carsten Rott, Gino Bolla
CSEM & Sintef Wafer Results
April 26, 2000
Daniela Bortoletto, Amitava Roy, Carsten Rott, Gino Bolla
Purdue University

2. Sintef Wafer Results 2 Wafers (#9, #24) have been received
IV & CV measurements are underway on wafer #24
Pixels for BTeV have been measured

3. Sintef-BTeV Pixels Early and inconsistent breakdown voltage
Depletion at
around 150V

4. Sintef-Purdue Diodes Cluster diodes breakdown at ~600V
Area = 1.75*1.75mm^2

5. Status of Measurements of CSEM (Purdue Zurich PSI) Wafer
IV and CV measurements on Wafer I + II are completed
Correlations between P-stop design and breakdown have been found
Parts of Wafer II have been wire bonded

6. Comparison (CSEM) Applying bias voltage from
n-side or p-side gives the same
results

7. Longterm measurement (CSEM)
An increase in leakage current is observed
Leakage current stabilizes after several hours
Bias voltage 300V (before breakdown)

8. Differences between wafers (CSEM)
Breakdown voltage in agreement.
Current per unit area
differs.

9. Current per unit area and wafer
Average current per unit area at 1.5*depl. Voltage
CSEM Wafer nA/cm^2
CSEM Wafer nA/cm^2
Sintef Wafer nA/cm^2

10. CSEM P-Stop designs Resistance D F G A,B,C - not metalized
D,E,F,G,H - metalized

11. Wire bonded CSEM Wafer II
n-side is up p-side wire bonded

12. Interpixel Measurements on CSEM Wafer (Pixel 20)

13. Biasing the whole pixel array
Voltage at Pixel in Pixel array 20 on CSEM Wafer 20
it can be seen that the whole pixel array is biased

14. Interpixel Measurements on CSEM Wafer
Test Structures on the
CSEM wafer, needs to be
wire bonded
measuring interpixel
capacitance and resistance

15. Conclusions & Goals
A correlation between P-stop design and breakdown has been found and can be fully understood soon
Interpixel measurements needs to be done