[Pending] Negative Bias Temperature Instability (NBTI) in p-MOSFETs: Characterization, Material/Process Dependence and Predictive Modeling (Part 1 of 3)

By Souvik Mahapatra

Electrical Engineering, IIT Bombay, India

Published on

Abstract

This is a presentation on Negative Bias Temperature Instability (NBTI), observed in p channel MOSFET devices. Though NBTI has been discovered more than 40 years ago, in the last 10 years it has become a very important reliability concern as the industry moved from thicker SiO2 to thinner SiON gate insulators in order to keep up with Moore's scaling law. The issue is still relevant and also very much exits in the recently introduced HKMG gate stacks.

This presentation is divided into 3 parts.

In the 1st part, I will start with a brief introduction to NBTI and show some important features. This will be followed by the description of fast and ultra-fast NBTI characterization methods that are necessary for proper estimation of device degradation. Information obtained from other characterization methods such as flicker noise, DCIV, charge pumping about process related pre-existing defects and stress generated defects will be covered next.

In the 2nd part, the impact of gate insulator processes on NBTI, especially the role of Hydrogen, Nitrogen and Fluorine will be discussed. We have extensively used the ultra-fast method to study NBTI parametric degradation in FETs having a wide variety of gate insulator processes and this will be covered next. As we shall see, NBTI is strongly gate insulator process dependent and this is a crucial information to understand the underlying physical mechanism of NBTI and its optimization via suitable process changes.

In the 3rd and final part, I will discuss NBTI physical mechanism, and build a simple model to explain measured data obtained from a wide variety of devices during DC stress, recovery following DC stress and during AC stress as a function of frequency and duty cycle. A predictive model for lifetime determination under use condition will also be discussed.

I will conclude the talk with the following take home messages. NBTI stress results in generation of interface traps together with hole trapping in process related pre-existing bulk oxide traps as well as in stress generated bulk oxide traps. Though there is some differences in generated interface and bulk traps, the process related pre-existing defects are primarily responsible for large difference in NBTI magnitude, time and temperature dependence seen in differently processed devices. NBTI can be improved by suitable process modifications that reduces these pre-existing defects. Bulk trap generation is significant at higher stress bias, but due to its stronger voltage acceleration, it becomes relatively negligible, though not zero, at use conditions. The interface trap contribution shows a strong universality in terms of DC and AC degradation, and is primarily responsible for long-time failure at use condition. Finally, once the hole trap contribution is taken into account, the Reaction-Diffusion (RD) model can successfully predict DC and AC NBTI results governed by contribution from interface traps.

Bio

Souvik Mahapatra received his PhD in Electrical Engineering from IIT Bombay, India, in 1999. He was at Bell Laboratories, Murray Hill, NJ, USA during 2000-2001. Since 2002 he is with the Department of Electrical Engineering, IIT Bombay, India, and presently holds the position of Professor. His research interests are in the area of characterization, modeling and simulation of CMOS and Flash memory devices, solar cells, and device reliability. He has published more than 120 papers in international journals and conferences, delivered invited talks at leading international conferences in the USA, Europe and Asia-pacific including at IEEE IEDM, delivered reliability tutorials at IEEE IRPS, and acted as a reviewer of several international journals and conferences. He also holds an honorary graduate faculty position at Purdue University, USA, is a distinguished lecturer of IEEE EDS, a senior member of IEEE and a fellow of the Indian National Academy of Engineering (INAE).

Credits

Co-contributors: M. A. Alam & A. E. Islam (Purdue University), E. N. Kumar, V. D. Maheta, S. Deora, G. Kapila, D. Varghese, K. Joshi & N. Goel (IIT Bombay)

Acknowledgement: C. Olsen and K. Ahmed (Applied Materials), H. Aono, E. Murakami (Renesas Electronics), G. Bersuker (SEMATECH), CEN IIT Bombay, NCN Purdue, Applied Materials, Renesas Electronics, SEMATECH, SRC / GRC

Cite this work

Researchers should cite this work as follows:

  • Souvik Mahapatra (2012), "Negative Bias Temperature Instability (NBTI) in p-MOSFETs: Characterization, Material/Process Dependence and Predictive Modeling (Part 1 of 3) ," http://nanohub.org/resources/13159.

    BibTex | EndNote

Tags

Negative Bias Temperature Instability (NBTI) in p-MOSFETs: Fast and Ultra-fast Characterization Methods (Part 1 of 3)
  • Negative Bias Temperature Instability (NBTI) in p-MOSFETs (Part 1 of 3) 1. Negative Bias Temperature Inst… 0
    00:00/00:00
  • Outline 2. Outline 115.75099945068359
    00:00/00:00
  • Outline 3. Outline 274.25099945068359
    00:00/00:00
  • Negative Bias Temperature Instability (NBTI) 4. Negative Bias Temperature Inst… 280.46099948883057
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  • A Simple Physical Framework of NBTI 5. A Simple Physical Framework of… 371.24199771881104
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  • Very Long Time Degradation 6. Very Long Time Degradation 490.31199741363525
    00:00/00:00
  • Dependence on Stress VG and Gate Leakage 7. Dependence on Stress VG and Ga… 541.18199634552
    00:00/00:00
  • Dependence on Stress EOX 8. Dependence on Stress EOX 675.00299549102783
    00:00/00:00
  • Parametric Degradation 9. Parametric Degradation 783.322995185852
    00:00/00:00
  • Gate Insulator Material / Process Impact 10. Gate Insulator Material / Proc… 905.45299243927
    00:00/00:00
  • Post Stress NBTI Recovery 11. Post Stress NBTI Recovery 975.44398975372314
    00:00/00:00
  • DC and AC Stress – Duty Cycle & Frequency 12. DC and AC Stress – Duty Cycl… 1118.7839860916138
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  • Motivation 13. Motivation 1205.4139833450317
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  • Outline 14. Outline 1251.3139848709106
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  • Issues with Measure-Stress-Measure Approach 15. Issues with Measure-Stress-Mea… 1278.0949850082398
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  • Ultra-Fast Measure-Stress-Measure (MSM) Method 16. Ultra-Fast Measure-Stress-Meas… 1350.6749868392944
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  • Ultra Fast MSM (Constant Current) Method 17. Ultra Fast MSM (Constant Curre… 1487.5859823226929
    00:00/00:00
  • On-The-Fly (OTF) IDLIN Method (Conventional) 18. On-The-Fly (OTF) IDLIN Method … 1592.435980796814
    00:00/00:00
  • Calculated Degradation from IDLIN Transient 19. Calculated Degradation from ID… 1685.4859838485718
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  • Conventional OTF Measurement Results 20. Conventional OTF Measurement R… 1810.2059850692749
    00:00/00:00
  • Ultra-Fast On-The-Fly (UF-OTF) IDLIN Method 21. Ultra-Fast On-The-Fly (UF-OTF)… 1889.3969869613648
    00:00/00:00
  • Degradation: Impact of 22. Degradation: Impact of "Time-Z… 2017.7879934310913
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  • Time Evolution of Long-time Degradation 23. Time Evolution of Long-time De… 2147.367995262146
    00:00/00:00
  • UF-OTF: Bias Dependence of Degradation 24. UF-OTF: Bias Dependence of Deg… 2236.0879964828491
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  • UF-OTF: Temperature Dependence of Degradation 25. UF-OTF: Temperature Dependence… 2305.8379964828491
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  • Mobility Correction 26. Mobility Correction 2404.8779973983765
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  • Summary 27. Summary 2550.4780035018921
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  • Outline 28. Outline 2668.7090063095093
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  • Background – The 29. Background – The "Philosophy… 2710.0690069198608
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  • Flicker Noise Measurement (Pre-stress) 30. Flicker Noise Measurement (Pre… 2794.0590047836304
    00:00/00:00
  • DCIV Measurements 31. DCIV Measurements 2899.7300024032593
    00:00/00:00
  • DCIV Measurements 32. DCIV Measurements 2999.0300054550171
    00:00/00:00
  • Correlation of DCIV to I-V Measurements 33. Correlation of DCIV to I-V Mea… 3137.4700078964233
    00:00/00:00
  • Charge Pumping Measurements 34. Charge Pumping Measurements 3214.4800100326538
    00:00/00:00
  • Correlation of CP to I – V Measurements 35. Correlation of CP to I – V M… 3316.5600118637085
    00:00/00:00
  • Impact of Stress on Flicker Noise 36. Impact of Stress on Flicker No… 3405.0310125350952
    00:00/00:00
  • Direct Comparison of Multiple Measurements 37. Direct Comparison of Multiple … 3493.3510122299194
    00:00/00:00
  • Comparison of CP and OTF-IDLIN (t0=1ms) 38. Comparison of CP and OTF-IDLIN… 3616.0620107650757
    00:00/00:00
  • Low Voltage (LV) SILC 39. Low Voltage (LV) SILC 3690.6720113754272
    00:00/00:00
  • Anomalous NBTI Degradation? 40. Anomalous NBTI Degradation? 3784.3020086288452
    00:00/00:00
  • Anomalous NBTI – Bulk Trap Generation 41. Anomalous NBTI – Bulk Trap G… 3821.9130086898804
    00:00/00:00
  • Hot Hole Induced Generation of Bulk Traps 42. Hot Hole Induced Generation of… 3901.90300655365
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  • Summary 43. Summary 4048.1730108261108
    00:00/00:00
  • Outline 44. Outline 4109.36300945282
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