Update on SET Reliability Project 18 Jun 2014 Keith Avery Program Manager Space Electronics Technology Space Vehicles Directorate Integrity Service Excellence Air Force Research Laboratory DISTRIBUTION STATEMENT A: Distribution A. Approved for public release; distribution unlimited.
Outline of Talk • Background • Our Focus • Fundamental Research – N/PBTI Research – Potential Trust Application – Modeling NBTI • Applied Research – Temperature Behavior of NBTI & HCI – JNT Demo/Eval • Future Plans • Summary 2 Distribution A, Approved for public release.
Reliability Research Group Rod Devine Think Strategically Lead, Experimenter Ken Kambour LEIDOS Modeling Ed Gonzales Think Strategically Process Engineer Duc Nguyen* COSMIAC Graduate UNM Camron Kouhestani COSMIAC Graduate UNM * Started work at Sandia on 1 Jun 14 3 Distribution A, Approved for public release.
Reliability of modern electronics less than satellite mission life • As IC feature size decreases, average IC lifetime decreases 1000 Process Variability confidence bounds Airplanes/ From: 100 Military/ State of the Art Mean Telecom Semiconductor Devices in Service 10 Future Aerospace Systems Computers life, yrs. L. Condra, Boeing, J. Qin laptop/palm 2004 1.0 and J.B. Bernstein, U of cell phones 2008 2012 Technology Maryland 2007 0.5 µ m 0.25 µ m 130 nm 65 nm 35 nm 0.1 1995 2005 2015 Year produced Note: between 1997 and 2008 the Reliability is maintained in RH devices in many service lifetime decreased by 10 x ways including by reducing performance to well below that of related commercial devices—1995 Note – MTTF IC = ( ∑ n Motorola PPC750 was 366 MHz, 2003 Rad 750 i=1 λ i ) -1 was 133 MHz (.26µ vs .25µ) where λ n = degradation rate for mechanism i and n is the number of mechanisms in the IC 4/14 Distribution A, Approved for public release.
Many (Especially in Government) are Increasingly Concerned About Reliability… Government Microcircuit Applications and Critical Technologies Conference 2014 Conference Theme: Reliability, Remembering the Recipe NIST-Sponsored Workshop (2014): Resilient, Robust, Reliable Electronic Materials and Devices Beyond Silicon As the end of silicon scaling approaches, new materials are being exploited…High-K (Hf based) gate dielectrics and metal gates are already in use…finally device-level quality has been obtained but their reliability issues are largely unexplored. In addition, the geometry of the basic planar device is being changed – FINFET’s, gate all around (nanowire)… Taking this all together, it means lifetime prediction of new devices is extremely difficult. … Generally, parts are qualified by accelerated testing. …accurate prediction of lifetime requires accurate models of the underlying physical mechanisms. We’ve focused on NBTI mechanisms for advanced space electronics 5 Distribution A, Approved for public release.
…but Industry is Not Reliability: fallacy or reality? Gonzalez, A. (INTEL)(Univ. Polytech. de Catalunya, Barcelona, Spain); Mahlke, S.; Mukherjee, S.;(INTEL) Sendag, R.; Chiou, D.; Yi, J.J.(Freescale) Source: IEEE Micro , v 27, n 6, p 36-45, Nov.-Dec. 2007 But, the majority of consumers Gonza´lez: Any idea on how we can measure care little about the reliable operation of reliability? electronic devices, and their concerns are Mukherjee: We fundamentally need decreasing as these devices become more a mechanism to measure these things. For disposable. In 2006, the average lifetime of hard errors, the problem may be tractable. a business cell phone was nine months. The For soft errors—induced by radiation—this average lifetimes of a desktop and a laptop is still a hard problem. For gradual errors, computer were about two years and one such as wear-out, we still don’t know how year, respectively……... Therefore, building to measure the reliability of an individual devices whose hardware functions flawlessly part . So, the answer is that, in many cases, for 20 years is simply unnecessary. we don’t know how to measure reliability. Industry will not attempt to provide lifetimes required for space applications 6 Distribution A, Approved for public release.
Outline of Talk • Background • Our Focus • Fundamental Research – N/PBTI Research – Potential Trust Application – Modeling NBTI • Applied Research – Temperature Behavior of NBTI & HCI – JNT Demo/Eval • Future Plans • Summary 7 Distribution A, Approved for public release.
Our Focus • NBTI, HCI, & EM dominate failure mechanisms in sub-45nm ICs – We focus on NBTI and HCI since HiREV has others working EM • Fundamental research – Identify physics of failure responsible for N/PBTI – Model time-dependent behavior of N/PBTI in circuits – Investigate synergy of radiation and reliability mechanisms – Identify physics of failure responsible for HCI • Applied Research – Explore new device types with improved intrinsic reliability • Currently, the Junctionless Nanowire Transistor (JNT) • Collaborate with colleagues – Develop measurement protocols that accelerate reliability testing and yield accurate results – Collaboration with multiple research establishments: NRL, SEMATECH, HIREV, Ariel U, Sandia, CINT, DMEA, … 8 Distribution A, Approved for public release.
Outline of Talk • Background • Our Focus • Fundamental Research – N/PBTI PoF Research – Potential Trust Application – Modeling NBTI • Applied Research – Temperature Behavior of NBTI & HCI – JNT Demo/Eval • Future Plans • Summary 9 Distribution A, Approved for public release.
Fundamental Research • Expanded research into NBTI and PBTI in 130 nm and 90 nm devices with SiON gate dielectrics • Began NBTI research on 32 nm high-k gate dielectric (HfO 2 /SiO 2 ) PMOS devices – Observed RC and FRC trapped charges with less IS – Establishing electric field and temperature dependencies • Evaluating comparative reliability of SiON and high-k gate dielectric devices • Began initial investigation of methods to evaluate complex circuit reliability based on individual device response RC: Recoverable Charge FRC: Field Recoverable Charge 10 IS: Interface State Distribution A, Approved for public release.
Previously Published Our Measurements Reveal the Multi-Defect Origin of NBTI Interface : Si-H + h + Si + + H or 1/2H 2 • We have developed a unique Insulator “bulk”: X 1 + h + X 1 + measurement protocol enabling Insulator “bulk”: X 2 + h + X 2 + Y extraction of the time dependence of 0.00 degradation components based -0.02 Interface state buildup IS IS Threshold voltage shift, ∆ V th (V) upon continuous & pulsed stressing -0.04 FRC -0.06 Field recoverable − This is essential for incorporation charge -0.08 into long-term reliability models -0.10 Recoverable charge − Now know several defects RC -0.12 V gs = -3.25 V types are responsible for NBTI V gs = 0 V -0.14 V gs = + 1.5 V then – 1V -0.16 0 2000 4000 6000 8000 10000 12000 Accumulated total time (seconds at 120o C) • Used protocol to measure lifetime characteristics of various transistors Findings: Contrary to widely held 1 hypothesis, increasing number of = MTTF ∑ ∑ IC n m 1 transistors in an IC contributes more = = 1 MTTF i 1 j i , j to reduced lifetime than change in transistor reliability 11 Distribution A, Approved for public release.
Our NBTI Measurements NBTI in HfO 2 0 IS FRC -0.05 IS: Interface States FRC: Field Recoverable Charge -0.1 ∆V Th (V) Recoverable Charge -0.15 -0.2 Vgs = 0V Vgs = 1.5V Vgs = -3.25V -0.25 0 500 1000 1500 2000 2500 3000 3500 4000 4500 Time (s) 12 Distribution A, Approved for public release.
Our NBTI Measurements NBTI in HfO 2 & SION NBTI in HfO 2 & SiON 0 HfO 2 has greater FRC HfO 2 has -0.05 greater RC -0.1 ∆V Th (V) NBTI in HfO2 NBTI in SiON -0.15 -0.2 SiON: 90 nm HfO 2 : 35 nm -0.25 0 500 1000 1500 2000 2500 3000 3500 4000 4500 Time (s) 13 Distribution A, Approved for public release.
Potential Trust Applications • Can NBTI characteristics of a device be used in fingerprinting an IC? – NBTI characteristics are determined by a combination of the manufacturing process and the transistor design – We expect they are “impossible” to duplicate NBTI in HfO 2 & SION 0 -0.05 -0.1 ∆V Th (V) -0.15 -0.2 -0.25 0 500 1000 1500 2000 2500 3000 3500 4000 4500 Time (s) 14 Distribution A, Approved for public release.
Reliability Modeling • Have taken first steps in developing “Permanent” interface 20 Permanent Threshold Voltage Shift (mV) lifetime modeling capability for state term (IS) + field 15 recoverable charge (FRC) complex circuits 10 • Model based on simple 5 measurements to estimate device 0 lifetime 0 1 2 3 4 5 6 7 8 10 10 10 10 10 10 10 10 10 Time (seconds) – Use high-temp to accelerate ∆V Th Δ f = 1.75% MTTF ~ 5 years – Use circuit simulation to measure the effect of permanent change in threshold voltage on a ring oscillator – When oscillator operation goes outside of circuit spec, device has failed • Validation of model in process 15 Distribution A, Approved for public release.
Outline of Talk • Background • Our Focus • Fundamental Research – N/PBTI PoF Research – Potential Trust Application – Modeling NBTI • Applied Research – Temperature Behavior of NBTI & HCI – JNT Demo/Eval • Future Plans • Summary 16 Distribution A, Approved for public release.
Recommend
More recommend
