Boris Revzin, Yaron Knafo 1 Ramped Voltage Test for MIM Capacitors - - PDF document

Ramped Voltage Test for MIM Capacitors in Wide Range of Ramp Rates Boris Revzin, Yaron Knafo

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Introduction

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Gal-El applied approach presented by TriQuint Semiconductor for in-line monitoring

• f MIM capacitors:

“Reliability Studies on Thin Metal-Insulator-Metal (MIM) Capacitors” Dorothy June M. Hamada and William J. Roesch TriQuint Semiconductor, ROCS 2008

Measurement Details

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• The vehicle was 300m x 300m MIM capacitor having SiN of 200 nm thickness.

154 units participated in each ramp.

• Starting ramp rates were 2.5 – 50 V/s with voltage step size 0.25V.
• Measurements had been performed by Keithley 2602 SMU controlled by internally

developed software.

• Two types of SiN had been tested A and B. Breakdown voltage had been defined at

10 mA/cm2 leakage current. This definition worked well for A type of SiN, while B type had significantly lower leakage current at hardware limiting voltage 190V. Therefore lower leakage current for breakdown definition and censored data sets for median breakdown voltage calculations were used.

Typical Result for 3 Ramp Rates

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Typical relation between ramp rates: DV12 > DV23 while 𝑆1 𝑆2 = 𝑆2 𝑆3 , and acceleration factor calculated g12 ≠ g23 ≠ g13.

Results: SiN type A

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Linear fit for median breakdown voltages for A type SiN Breakdown is defined at leakage current 10 mA/cm2. Measurements performed at 1, 2.5, 5, 10, 40, and 160 V/s ramp rates. Correlation is greater than 0.99.

Results: SiN type B

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Linear fit for median breakdown voltages for B type SiN. Breakdown is defined at leakage currents 20, 70, and 100 µA/cm2 for the wafers W16, W18, and W17 respectively. Example of censored data. Wafer W17, 2 V/s.

TriQuint Data Set

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Fitting to TriQuint ramped voltage test data. SiN thickness is 50 nm.

Conclusions

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• Linear dependence of median breakdown voltage on logarithm of ramp rate had

been

• bserved

for SiN

• f

different quality and moreover for different manufacturers and thicknesses indicating that this is a common behavior.

• Linear region provides a technique for ramped voltage testing optimization by

avoiding time consuming measurements at low ramp rates and also provides extrapolation to very low ramp rates unacceptable for practical applications.

Acknowledgements

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Alon Soloshansky

For support of all measurements including equipment and software.

Gal-El management

For permission to publish these results.

Thank you!

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