State of Demonstrated HV GaN Reliability and Further Requirements APEC 2015 Charlotte, NC Tim McDonald Steffen Sack, Deepak Veereddy, Yang Pan, Hyeongnam Kim, Hari Kannan, Mohamed Imam
Agenda What Composes a High Voltage Device Qualification? How to ensure GaN devices meet lifetime requirements of a given application? “JEDEC” qualification insufficient! Application stability? DC stability? Multiple aspects/components required Multi dimensional approach is proposed Data for each dimension for HV devices provided Further work 2
Sample Silicon Qualification Test Plan Accelerated Environment Stress Tests REQUIRED RELIABILITY TESTS Part Type Part no “X” Test Conditions Duration TC -55°C/150°C 1000 cy H3TRB 85°C/85%RH/100V 1000 hrs /480V HTRB 150°C/960V 1000 hrs HTGB 150°C/20V 1000 hrs IOL delta Tj = 100°C 5,000 cy AC 121°C/15psig 96 hrs Parameter measurements @ 0/168/500/1000 0/168/500/1000 0/168/500/1000 0/168/500/1000 0/2500/5000 0/96 Quantity 3 x 77 3 x 77 3 x 77 3 x 77 3 x 77 3 x 77 On what basis can one assume that the test
Ingredients to Drive a Qualification QRP Qualification Test Plan Quality Requirement Profile Rel. Investigation at Development Phase Degradation Models Application Profile Qualification Released Product Copyright © Infineon Technologies AG 2013. All rights reserved.
Ingredients to Drive a Qualification QRP Qualification Test Plan Quality Requirement Profile Rel. Investigation at Development Phase Degradation Models Application Profile Qualification Released Product Copyright © Infineon Technologies AG 2013. All rights reserved.
Application Profile - The Application Profile displays the technical details of the different target applications in respect to the expected use conditions at the customer side. - Within the Application Profile the following information are given: - Application Lifetime - Operating hours, duty cycles - Switching frequencies - Currents, voltages, temperatures at different load conditions - Use times of different load profiles - Amount/Time of abnormal use conditions within lifetime (e.g.
HV GaN HEMT dynamic Rds(on): Today At 75C and 150C : Rds(on) is stable after bias (increase is due to expected change with temperature). 25 to 150C, 100V to 480V, fsw = 100 Hz, DC = 1% d-Rdson (Ohm) 0.4 0.35 After bias RDSon is stable with voltage 0.3 0.25 0.2 1us 0.15 5us 0.1 0.
Device Ruggedness: Long-Term PFC (Boost) Application Testing • 120 Tcase (oC) 100 • 225 W, 120V:500V DC to DC conversion at 100 kHz 80 60 Measured package Temperature is a proxy for power dissipated: Δ T = RTH x Ploss , which correlates to Efficiency.
Ingredients to Drive a Qualification QRP Qualification Test Plan Quality Requirement Profile Rel. Investigation at Development Phase Degradation Models Application Profile Qualification Released Product Copyright © Infineon Technologies AG 2013. All rights reserved.
QRP - Quality Requirement Profile - The QRP displays the development targets of a new technology/product in respect to it’s reliability performance and the target applications - Within the QRP following information are given: - General definition of target applications (Technical details in application profile) - Maximum operation voltages and currents - Operation temperature range - ESD classification - MSL-class definition - Lifetime targets/Failure rates for device, dielectrics and metallization - Defini
Example Element of Quality Requirement Temp. Profile Conversion The different temperatures are corresponding to varying levels of output power and ambient temperatures over the application lifetime. The electrical biased tests has to consider this thermal profile. Using acceleration models the application profile can be converted to useful stress conditions. Converted Temp. Profile to Mean Temp. over Lifetime Temp. Profile of Application Time /h Temp.
Ingredients to Drive a Qualification QRP Qualification Test Plan Quality Requirement Profile Rel. Investigation at Development Phase Degradation Models Application Profile Qualification Released Product Copyright © Infineon Technologies AG 2013. All rights reserved.
Reliability Investigation at Development Phase - Check reliability capabilities starting with first full design wafers - Perform DoE’s (Design of Experiment) during learning cycles and assess reliability to find optimal process flow and define process windows - Confirm a sufficient quality before starting the final qualification phase - Learn about the typical failure modes and create degradation/lifetime models - Adaption or creation of test methods to address new failure mechanisms and modes - Based on de
Reliability of 600V devices in HTRB (150C, 480V) Interval Lot number • Early Reliability data for 3 lots , 77 pcs each • Rdson stable through 1000 hours
Reliability of 600V GaN Devices up to 5,000 hours of HTRB • 600V GaN devices are inherently reliable • Source-drain resistance Rdson of 600 V rated cascode switch for a population of representative cascoded GaN-on-Si based HEMT devices with Wg = 120 mm, under a drain bias of 480 V and 0 gate bias for 5000 hrs at 150 C.
Ingredients to Drive a Qualification QRP Qualification Test Plan Quality Requirement Profile Rel. Investigation at Development Phase Degradation Models Application Profile Qualification Released Product Copyright © Infineon Technologies AG 2013. All rights reserved.
MTTF and FIT Rate for HV Gate Dielectric Material MTTF & FIT Rate vs Stress voltage 15 1010 10 13 1011 108 106 109 104 107 102 105 100 103 101 10-1 FIT rate at RT FIT rate at 85C FIT rate at 110 C FIT rate at 150 C 10-2 FIT rate (FIT) MTTF (hrs) 10 MTTF at RT MTTF at 85C MTTF at 110C MTTF at 150C Preliminary predictions: MTTF > 108 hrs; FIT~1 @ application conditions 10-4 10-6 5 6 7 8 9 10 11 12 13 14 15 16 17 18 VGSS(V) Degradation models required for component structures of the GaN H
Time Dependent Dielectric Breakdown Related Reliability Ceramic Capacitors : Accelerated Stress Conditions Prokopowicz and Vaskas Equation Michael S. Randall et al (KEMET), Proceedings of CARTS 2003 pp.
Preliminary Reverse Bias Lifetime Estimate for early HV GaN Devices MTTF [Hrs] 25C 1E+11 1E+10 1E+9 1E+8 1E+7 1E+6 1E+5 1E+4 1E+3 1E+2 1E+1 1E+0 1E-1 Based on Testing to failure at 825V, 800V and 775V: Projected meantime to failure at 480V bias (25C) is 2E7 hours or >2200 years.
Preliminary Reverse Bias Lifetime Estimate for early HV GaN Devices MTTF [Hrs] 25C 1E+11 1E+10 1E+9 1E+8 1E+7 1E+6 1E+5 1E+4 1E+3 1E+2 1E+1 1E+0 1E-1 -Use accelerated data to set test conditions for 1,000 hr testing (ie: to generate a meaningful Qualification Test Plan) -Use statistics to calculate FIT rate at required lifetime and use conditions 300 350 400 450 500 550 600 650 Stress Voltage [V] Engineering Evaluation of Early Samples 700 750 800 850 900
Ingredients to Drive a Qualification QRP Qualification Test Plan Quality Requirement Profile Rel. Investigation at Development Phase Degradation Models Application Profile Qualification Released Product Copyright © Infineon Technologies AG 2013. All rights reserved.
Qualification Test Plan The testplan includes: - Definition of sample size in respect to internal and common standards like JEDEC, Q101, etc. - All tests and test parameters to address all known degradation modes. - All tests with critical reliability impact seen during the development phase testing where the test parameters reflect the outcome of the degradation and acceleration models.
Sample Silicon Qualification Test Plan Accelerated Environment Stress Tests REQUIRED RELIABILITY TESTS Part Type Part no “X” Test Conditions Duration TC -55°C/150°C 1000 cy H3TRB 85°C/85%RH/100V 1000 hrs /480V HTRB 150°C/960V 1000 hrs HTGB 150°C/20V 1000 hrs IOL delta Tj = 100°C 5,000 cy AC 121°C/15psig 96 hrs Parameter measurements @ 0/168/500/1000 0/168/500/1000 0/168/500/1000 0/168/500/1000 0/2500/5000 0/96 Quantity 3 x 77 3 x 77 3 x 77 3 x 77 3 x 77 3 x 77 With knowledge of Failure mechanisms and a
Ingredients to Drive a Qualification QRP Qualification Test Plan Quality Requirement Profile Rel. Investigation at Development Phase Degradation Models Application Profile Qualification Released Product Copyright © Infineon Technologies AG 2013. All rights reserved.
Summary -To qualify GaN on Si devices it is insufficient to follow standard Silicon qualification matrix -5 required elements to a qualification are described: the qual matrix is only 1 component -Establishing GaN device performance to all 5 elements will assure reliable operation to a specified application -Preliminary GaN device reliability data is provided to illustrate the elements -A full qualification will include fully addressing all 5 dimensions In a single phrase: To qualify GaN on Silicon it is n
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