T082112_BUY25CS54A

Single-Event Effect Testing of the Infineon Technologies

BUY25CS54A (ESCC 5205/027) n-Type Power MOSFET

J.-M. Lauenstein1, M.C. Casey

1, A.D. Topper

2, A.M. Phan

2, and E.P. Wilcox

2

NASA Goddard Space Flight Center

Code 561.4, Radiation Effects and Analysis Group

8800 Greenbelt RD

Greenbelt, MD 20771

Test Date: 21 August 2012

Report Date: 28 September 2012

1NASA Goddard Space Flight Center, Greenbelt, MD USA

2MEI Technologies, Inc., Greenbelt, MD USA

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I. Introduction and Summary of Test Results

This study was being undertaken to determine the single event effect susceptibility of the radiation-

hardened BUY25CS54A power MOSFET recently developed by Infineon Technologies and ESCC

qualified. Heavy-ion testing was conducted at the Texas A&M University Cyclotron Single Event Effects

Test Facility (TAMU). Its purpose was to evaluate this device as a candidate for use in NASA flight

projects.

All failures during these tests were due to SEGR. SEGR is defined to have occurred when the gate

current exceeds the vendor specified maximum gate-source leakage current (+/- Igss). Tests were

conducted at normal beam incidence in air, with a few additional samples tested at 30 , 45 , and 60 off-

normal incidence. A summary of the minimum last pass/first fail drain-source voltage (Vds) for a given

gate-source voltage bias (Vgs) is provided in Table I below as a function of the ion species and beam

angle of incidence, as well as energy, range, and LET at the surface of the device under test (DUT).

Incident energy, range, and LET were determined by the TAMU Seuss software based upon SRIM. The

total number of devices tested under each beam and bias condition is shown in the final column. Data

taken under normal beam incidence are plotted in Figure 1 as the last passing Vds. Details are provided in

the Results section below. It should be noted that it is assumed for an individual sample that operation at

bias conditions below those yielding no failure during test will also result in no failure. For example,

samples passing at -10 Vgs and the full 250 Vds are assumed to pass at 0 and -5 Vgs at 250 Vds.

Table 1: Summary of Heavy-Ion Test Results for Individual Samples

Ion

Species

Surface-Incident

Energy Range

Surface-Incident

LET

Angle of

Incidence Vgs

Maximum Last

Passing Vds

Minimum Vds at

Failure

Sample Size

(MeV) ( m) (MeV·cm2/mg) (degrees) (V) (V) (V) #

Ag 1289 119.3 42.2

0

0 250 -- 1

-10 250 -- 2

-15 250 -- 3

Xe 1512 119.7 51.5

0

0 250 -- 1

-10 250 -- 2

-15 250 -- 3

Au 2247 118.1 85.4

0

0 250 -- 1

-5 250 -- 1

-10 250 -- 5

-15 130 140 6

30 -15 220 250 1

45 -15 250 -- 1

60 -15 250 -- 1

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Figure 1. Maximum passing Vds bias for each DUT as a function of Vgs bias during irradiation.

Error bar on -15 Vgs Au data point shows step size between last passing Vds and Vds at failure.

II. Devices Tested

The sample size for this testing was 10 pieces. The part is manufactured by Infineon Technologies as

one of the first of their new radiation-hardened power MOSFET line.

The device is a radiation hardened 54 A, 250 V discrete n-channel superjunction power MOSFET,

part # BUY25CS54A (ESCC 5205/027). Samples were provided by Infineon Technologies in November,

2011 in delidded SMD-2 packages with a lot date code of 1146.50. The pieces were visually inspected

and electrically characterized by Alyson Topper, MEI Technologies at GSFC prior to test. The die area is

0.86 cm2; the cell topology has no specific orientation with respect to the die. A picture of a delidded

sample is shown in Figure 2.

Figure 2. Photograph of delidded SMD-2 packaged DUT.

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III. Test Facility

Facility: Texas A&M University Cyclotron Single Event Effects Test Facility, 15 MeV/amu tune.

Flux: 5 x 103 ions/cm

2/s to 1 x 10

4 ions/cm

2/s.

Fluence: All tests were run to the lesser of 5 x 105 ions/cm

2 or until destructive events occurred.

Ion species: Ag, Xe, and Au. The table below shows the surface-incident beam properties as

calculated by the TAMU SEUSS software.

Table 2. Ion Beam Properties

Ion: Air Gap

(cm)

Surface Energy

(MeV)

Surface LET

(MeV·cm2/mg)

Range

( m)

Angle of Incidence

(Degrees)

109Ag

3 1289 42.2 119.3 0

129Xe

3 1512 51.5 119.7 0

197Au

3 2247 85.4 118.1 0, 30, 45, 60

IV. Test Setup

The test circuit and block diagram, as shown in Figures 3 and 4, for the power MOSFET contains a

Keithley 2400 source meter to provide the gate voltage (set to 0 V, -5 V, -10 V, or -15 V during

irradiation) while measuring the gate current. A filter is placed at the gate node of each device under test

(DUT) to dampen noise at the gate. A Keithley 2410 source meter provides the appropriate Vds while

measuring the drain current; a 500 Ω resistor is optionally switched into series with the Keithley 2410 to

protect it from sudden high-current transients; it is switched out during device characterization tests. Gate

current is limited to 1 mA, and drain current limited to 10 mA, and recorded via GPIB card to a desktop

computer at approximately 250 ms intervals. A Tektronix MSO5104 digital oscilloscope monitors voltage

transients across the 1 drain sense resistor via BNC cable. All equipment is plugged into a power

conditioner.

If desirable for error mode analysis, a current limiting resistor may be jumpered into series with the

drain to protect the DUT from destructive SEB. Six DUTs can be mounted on the test board via daughter

cards with SMD-2 sockets and individually accessed via dry Reed relays controlled by an Agilent DAQ

34907A data acquisition/switch unit. All terminals of the devices not under test are then floating. Testing

was conducted in air with the DUT centered within the 1 inch beam diameter. Ion exposures were

conducted at either 0º, 30º, 45º, or 60º tilt angle (where 0º tilt is normal incidence to the DUT).

Photographs of the test setup and DUT test board are shown in Figure 5.

The test setup is controlled via custom LabView codes written by Alyson Topper and Hak Kim, MEI

Technologies, for this test. One program controls the source measuring units (SMUs), gate current limit,

oscilloscope monitoring and transient capture, and gate and drain current sampling and recording. The

second LabView code is designed to perform a parametric analysis of each DUT prior to irradiation and

following each beam run, recording if selected, Ig and Id as a function of Vgs (gate stress test to test the

integrity of the gate dielectric), Ids as a function of Vgs at various fixed Vds values for evaluation of total

ionizing dose effects, gate threshold voltage (Vth), drain-source breakdown voltage (BVdss), and zero

gate voltage drain current (Idss).

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Figure 3. Equivalent test circuit for the BUY25CS54A power MOSFET.

Figure 4. Block diagram of test setup.

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Figure 5. Upper Left: DUT board and equipment in beam cave; Upper Right: DUT positioned in

beam line. Lower Left: DUT in socket; Lower Right: DUT positioned at 60 to beam line.

V. Test Results

Tests were performed at Texas A&M University Cyclotron Single Event Effects Test Facility on

August 21, 2012. The monoenergetic ion beams used are listed in Table 2 above and include 1289 MeV

Ag, 1512 MeV Xe, and 2247 MeV Au. All tests with Ag and Xe were conducted with the beam at normal

angle of incidence to the DUT. Under Au irradiation, DUTs were tested at normal incidence, and one

DUT each was tested at 30 , 45 , and 60 off-normal tilt angle to the beam. At 60 , the effective range of

the Au ions is reduced from 118.1 m to 59 m, such that the effective ion penetration depth before the

Bragg peak is only 32.5 m. This effective penetration is insufficient to place the Bragg peak beyond the

epilayer into the substrate; however, based on past angular studies and the sufficient penetration at 45 ,

we do not expect device failure from longer-range Au ions at this oblique angle under -15 Vgs and drain

bias conditions up to the rated 250 V.

Prior to the initial beam run and following each run, the drain-source breakdown voltage was

measured to test the integrity of the drain-source connection, and a post-irradiation gate stress (PIGS) test

was performed in which the gate and drain currents were measured while at a fixed 0 Vds the gate voltage

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was swept from 0 V to 20 V, then from 0 V to -20 V, in 5 V increments. Each voltage step was held for 1

s to allow settling prior to the current reading and to stress the gate per MIL-STD_750-1 TM1080.1.

Failure was defined as the gate current exceeding the manufacturer gate-source leakage current (Igss)

specification of 100 nA during the beam run or during the PIGS test, and/or a sudden, sustained increase

in the drain current during the beam run.

All devices tested under Ag and Xe ion beams passed at the full rated 250 Vds with the gate biased up

to -15 V. Failures occurred within the rated operating bias range only under Au irradiation when the gate

was biased at -15 V. These failures occurred at 0 and 30 angles of incidence and were due to gate

rupture and occurred during the beam run. BVdss remained intact for all DUTs. The threshold Vds under

which SEGR occurred increased at 30 , with no failures occurring at 45 or 60 , suggesting a sharp fall-

off of SEGR sensitivity with angle as expected. Post-test examination under a 90X stereoscope did not

reveal any surface burn marks, in keeping with failures due to gate rupture. Table I in Section I

summarizes the heavy-ion test results for each bias for the beam condition with more details provided

below in Table 3; Figure 1 in Section I plots the bias conditions at which no failures occurred for any

DUT. Device electrical specifications are provided in Appendix A, as well as pretest electrical

characterizations performed at GSFC prior to testing, and on-site pre-run DUT Igss and BVdss functional

tests. Complete results are in Appendix B, PIGS test results in Appendix C, and example striptape current

measurements in Appendix D. Appendix E contains ion beam uniformity and other beam log information.

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Table 3. Summary of Heavy-Ion Test Results for Individual Samples

Ion

Species

Surface-Incident

Energy Range

Surface-Incident

LET

Angle of

Incidence Vgs

Maximum Last

Passing Vds

Minimum Vds

at Failure

(MeV) ( m) (MeV·cm

2/mg) (degrees) (V) (V) (V)

Ag 1289 119.3 42.2

0

0 250 --

-10 250 --

250 --

-15

250 --

250 --

250 --

Xe 1512 119.7 51.5

0

0 250 --

-10 250 --

250 --

-15

250 --

250 --

250 --

Au 2247 118.1 85.4

0

0 250 --

-5 250 --

-10

250 --

250 --

250 --

250 --

250 --

-15

--* 225

125 150

140 150

130 140

130 140

140 150

30 -15 220 250

45 -15 250 --

60 -15 250 --

*DUT failed under first bias condition.

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Appendix A

Table A1. BUY25CS54A Manufacturer-Specified Electrical Parameters (Partial List)

Parameter Condition MIN MAX Units

Gate Threshold Voltage (VGSth) Vds = Vgs, Id = 1 mA 2 4 V

Zero Gate Voltage Drain Current (Idss) Vds = 200 V, Vgs = 0 V

25 A

Drain-Source Breakdown Voltage (BVdss) Vds = 0 V, Id = 0.25 mA 250

V

Gate-Source Leakage Current (Igss) Vgs = +/- 20 V, Vds = 0 V

+/-100 nA

Static Drain-Source Resistance (Rds_on) Vgs = 10 V, Id = 34 A

0.03

Forward Voltage (Vsd) IF = 54 A, Vgs = 0V

1.2 V

Table A2. Pretest Electrical Characterization at GSFC, May 29, 2012 (DUTs mounted in test board; measurements

may reflect capacitor leakage currents when these exceed actual DUT performance.)

Part SN Vth BVdss Idss Igss + Igss -

(V) (V) ( A) (nA) (nA)

2 3.06 282 0.24 1.44 -1.38

3 3.07 284 0.229 2.62 -2.43

4 3.07 282 0.17 0.37 -0.41

5 3.07 288 0.173 0.42 -0.48

6 3.07 280 0.256 1.48 -1.45

7 3.08 288 0.27 2.56 -2.40

8 3.04 282 0.19 0.43 -0.49

9 3.07 288 0.30 0.60 -0.60

10 3.05 282 0.19 0.38 -0.44

14 3.07 280 0.26 0.46 -0.45

Table A3. On-Site Pre Beam Run Aliveness Tests

(Note: repeated upon reinsertion into socket)

Part SN BVdss Igss + Igss -

(Volts) (nA) (nA)

4 280 2.21 -2.36

7 286 2.39 -2.53

3 284 0.54 -0.68

3 284 0.64 -0.75

7 285 2.20 -2.35

2 279 0.51 -0.64

2 284 0.79 -0.83

6 285 0.63 -0.79

5 279 0.64 -0.80

8 286 0.79 -0.97

9 286 5.06 -5.24

10 286 0.81 -0.97

14 280 0.82 -0.99

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Appendix B

Table B1. Raw test data from 21 August 2012. Beam diameter = 1”; LET, energy, and range are after beam airgap of 3cm.

NOTE: Ion characteristics in table are from TAMU’s SEUSS software based upon SRIM 1998.

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Appendix C

Table C1. Selected Pre- and Post-Irradiation Gate Stress Test Results

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Appendix D

Figure D1. Strip tape data from DUT 2, run 164: 2247 MeV Au. Run bias conditions: -15 Vgs,

225 Vds. Beam shuttered after about 6 seconds. Drain current shown on smaller scale in lower

plot.

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Figure D2. Strip tape data from DUT 6, run 170: 2247 MeV Au. Run bias conditions: -15 Vgs,

150 Vds. Beam shuttered after about 28 seconds.

Figure D3. Strip tape data from DUT 5, run 175: 2247 MeV Au. Run bias conditions: -15 Vgs,

150 Vds. Drain current shown on smaller scale in lower plot. Beam shuttered after about 34

seconds.

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Figure D4. Strip tape data from DUT 8, run 178: 2247 MeV Au. Run bias conditions: -15 Vgs,

140 Vds. Beam shuttered after about 40 seconds.

Figure D5. Strip tape data from DUT 9, run 181: 2247 MeV Au. Run bias conditions: -15 Vgs,

140 Vds. Drain current shown on smaller scale in lower plot. Beam shuttered after about 16

seconds.

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Figure D6. Strip tape data from DUT 10, run 184: 2247 MeV Au. Run bias conditions: -15 Vgs,

150 Vds. Drain current shown on smaller scale in middle plot and gate current in lower plot reveal

unusual succession of charge collection events or possible facility noise. Beam shuttered after

about 26 seconds.

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Figure D7. Strip tape data from DUT 14, run 210: 2247 MeV Au at 30 incidence. Run bias

conditions: -15 Vgs, 250 Vds. Drain current shown on smaller scale in lower plot. Beam shuttered

after about 53 seconds.

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Appendix E

Table E1. TAMU Beam Log (Selected Sections)

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