A NEUTRON IRRADIATION DEVICE FOR THE TESTING OF A NEUTRON IRRADIATION DEVICE FOR THE TESTING OF MICROELECTRONIC COMPONENETS TO BE USED IN THE MICROELECTRONIC COMPONENETS TO BE USED IN THE

RADIATION ENVIRONMENT OF HIGH-ENERGY RADIATION ENVIRONMENT OF HIGH-ENERGY PARTICLE ACCELERATORS AT DESYPARTICLE ACCELERATORS AT DESY

B. MukherjeeB. Mukherjee11, D. Makowski, D. Makowski22, A. Kalicki, A. Kalicki33, D. Rybka, D. Rybka33, , M. GreckiM. Grecki2 2 , S. Simrock, S. Simrock11

11Deutsches Elektronen Synchrotron, Hamburg, GermanyDeutsches Elektronen Synchrotron, Hamburg, Germany22Department of Microelectronics and Computer Science, TUL, PolandDepartment of Microelectronics and Computer Science, TUL, Poland

33Institute of Electronic Systems, WUT, PolandInstitute of Electronic Systems, WUT, Poland

1212thth International MIXDES Conference, 22-25 June 2005, Krakow, Poland International MIXDES Conference, 22-25 June 2005, Krakow, Poland

INTRODUCTIONINTRODUCTION

A significant number of microelectronic instrumentation and control A significant number of microelectronic instrumentation and control devices vital to the operation of the VUV-Free Electron Laser (FEL) devices vital to the operation of the VUV-Free Electron Laser (FEL) of DESY will be located in the close vicinity of the 1.2 GeV super-of DESY will be located in the close vicinity of the 1.2 GeV super-conducting electron linac driving the FEL.conducting electron linac driving the FEL.

During the linac operation the microelectronic components will be During the linac operation the microelectronic components will be subjected to parasitic radiation field, primarily made of brems-subjected to parasitic radiation field, primarily made of brems-strahlung and photoneutrons. strahlung and photoneutrons.

The radiation exposure will trigger Soft-Error (Single Event Upset) The radiation exposure will trigger Soft-Error (Single Event Upset) as well as Permanent Damage in the electronic circuitry. as well as Permanent Damage in the electronic circuitry.

We have developed a variable energy neutron irradiation device for We have developed a variable energy neutron irradiation device for the radiation effect testing of microelectronic components. the radiation effect testing of microelectronic components.

The device is based on a The device is based on a 241241Am-Be(Am-Be(, n) source placed at the centre , n) source placed at the centre of a water filled jar acting as neutron moderator. The neutron energy of a water filled jar acting as neutron moderator. The neutron energy variation is accomplished by varying the jar diameter. variation is accomplished by varying the jar diameter.

RADIATION EFFECTS IN MICROELECTRONICSRADIATION EFFECTS IN MICROELECTRONICS

THE NEUTRON IRRADIATION DEVICETHE NEUTRON IRRADIATION DEVICE

LegendLegendB: Thermal Neutron Shield (Borated Polyethylene)B: Thermal Neutron Shield (Borated Polyethylene)D: Device under Test (DUT)D: Device under Test (DUT)H: TableH: TableJ1, J2: Jars (16 and 33 cm radius respectively)J1, J2: Jars (16 and 33 cm radius respectively)P: StandP: StandS: S: 241241Am-Be Neutron sourceAm-Be Neutron sourceT: Tripod (Source holder)T: Tripod (Source holder)

Photograph of the neutronPhotograph of the neutronIrradiation device showing Irradiation device showing

diverse types of DUT diverse types of DUT under irradiation. under irradiation.

CHARACTERISTICS OF THE NEUTRON RADIATION FIELDCHARACTERISTICS OF THE NEUTRON RADIATION FIELD

The Reference Neutron SpectraThe Reference Neutron Spectra(a) Un-moderated, En (av) = 5.2 MeV(a) Un-moderated, En (av) = 5.2 MeV(b) Moderated (6.9 cm H(b) Moderated (6.9 cm H22O), En (av) = 4.1 MeVO), En (av) = 4.1 MeV

(c) Moderated (15.9 cm H(c) Moderated (15.9 cm H22O), En (av) = 3.2 MeVO), En (av) = 3.2 MeV

The areas under the histogram (a), (b) and (c)The areas under the histogram (a), (b) and (c)are normalised to unity.are normalised to unity.

LegendLegendTmod = Moderator (H2O) ThicknessTmod = Moderator (H2O) ThicknessSDD = Source to Detector DistanceSDD = Source to Detector Distance

Hnm = Measured Neutron Dose Equiv.Hnm = Measured Neutron Dose Equiv.Hnc = Calculated Neutron Dose EquivHnc = Calculated Neutron Dose EquivHgm = Measured Gamma Dose Equiv.Hgm = Measured Gamma Dose Equiv. * With thermal neutron shield* With thermal neutron shield

VERIFICATION OF THE REFERENCE RADIATION FIELDVERIFICATION OF THE REFERENCE RADIATION FIELD

Neutron DetectorNeutron DetectorThe Neutron Dose Equivalent at The Neutron Dose Equivalent at various moderator thicknesses various moderator thicknesses was verified by Superheated was verified by Superheated Bubble Dosimeters (Bubble Dosimeters (Gamma Gamma InsensitiveInsensitive) )

Gamma DetectorGamma DetectorThe background Gamma Dose at The background Gamma Dose at

various moderator thicknesses various moderator thicknesses was verified by a PIN Diode based was verified by a PIN Diode based

miniature Electronic Dosimeter miniature Electronic Dosimeter ((Neutron InsensitiveNeutron Insensitive) )

TESTING OF MICROELCTRONIC COMPONENTSTESTING OF MICROELCTRONIC COMPONENTSWe have irradiated the following itemsWe have irradiated the following items

(1) Commercially available SRAM chips of 256, 512, 1024 and 2048 kB (1) Commercially available SRAM chips of 256, 512, 1024 and 2048 kB memory density (s. Table below)memory density (s. Table below)

(2) Two miniature CCD Cameras(2) Two miniature CCD Cameras

Irradiation ParametersIrradiation Parameters

(1) Un-moderated neutrons(1) Un-moderated neutrons(2) Neutrons moderated with 6.9 cm H2O layer(2) Neutrons moderated with 6.9 cm H2O layer(3) Moderated neutrons (as above),Shielded (3.5 mm Bor-Poly) Irradiation device(3) Moderated neutrons (as above),Shielded (3.5 mm Bor-Poly) Irradiation device

Specifications of the SRAM Specifications of the SRAM (Static Random Access (Static Random Access

Memory) Chips used in this Memory) Chips used in this Investigation.Investigation.

TEST RESULTSTEST RESULTS

Number of SEU in 512 kB SRAM Chips induced Number of SEU in 512 kB SRAM Chips induced by neutrons for three exposure modes. by neutrons for three exposure modes.

Neutron induced SEU in CCD Neutron induced SEU in CCD Cameras for two exposure modes.Cameras for two exposure modes.

Results showing the neutron Results showing the neutron irradiation effects in SRAM irradiation effects in SRAM

chips of four different chips of four different memory densities.memory densities.

SUMMARY AND CONCLUSIONSUMMARY AND CONCLUSIONWe have demonstrated the construction and operation principles of a simple We have demonstrated the construction and operation principles of a simple variable energy neutron irradiation device based on an isotopic neutron source. variable energy neutron irradiation device based on an isotopic neutron source.

The primary neutrons from the The primary neutrons from the 241241Am-Be (Am-Be (, n) source with an energy of 5.2 MeV was , n) source with an energy of 5.2 MeV was moderated with 6.9 (Jar 1) and 15 (Jar 2) cm thick water layers to obtain the neutron moderated with 6.9 (Jar 1) and 15 (Jar 2) cm thick water layers to obtain the neutron radiation field of 4.1 and 3.2 MeV average energy respectively. radiation field of 4.1 and 3.2 MeV average energy respectively.

The system consists of a The system consists of a 241241Am-Be (Am-Be (, n) source located at the centre of an assembly , n) source located at the centre of an assembly of concentric polyethylene jars of 8.0 and 16.5 cm radius respectively. of concentric polyethylene jars of 8.0 and 16.5 cm radius respectively.

The neutron dose equivalents at different configurations (Moderator layer The neutron dose equivalents at different configurations (Moderator layer thickness) and the corresponding gamma background doses were estimated thickness) and the corresponding gamma background doses were estimated with Superheated bubble dosimeter and PIN diode dosimeter respectively. with Superheated bubble dosimeter and PIN diode dosimeter respectively.

A cylindrical thermal neutron shield made of 3.5 mm thick borated polyethylene A cylindrical thermal neutron shield made of 3.5 mm thick borated polyethylene sheet was used to attenuate the thermal neutron component of the irradiation field.sheet was used to attenuate the thermal neutron component of the irradiation field.

A radiation hardness of various microelectronic devices like, SRAM and FPGA A radiation hardness of various microelectronic devices like, SRAM and FPGA chips as well as CCD cameras have been tested using the above device prior to chips as well as CCD cameras have been tested using the above device prior to their installation in the high-energy accelerator environment at DESY.their installation in the high-energy accelerator environment at DESY.

THANK YOU FOR YOUR ATTENTIONTHANK YOU FOR YOUR ATTENTION(bhaskar.mukherjee@desy.de)(bhaskar.mukherjee@desy.de)