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The 6 th INFN National School on Detectors and Electronics. GUO Gang Mar. 25 th , 2015 , Padova , Italy. Single-Event Effect Activities at CIAE. Main Content. Introduction about CIAE SEE and space radiation environment Ground simulation test
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The 6th INFN National School on Detectors and Electronics GUO Gang Mar. 25th, 2015,Padova, Italy Single-Event Effect Activities at CIAE
Main Content • Introduction about CIAE • SEE and space radiation environment • Ground simulation test • Main SEE ground simulation test sites in China • HI-13 tandem accelerator at CIAE • Broad-beam irradiation technique and it application • Application technique of highly stripping charge state ion beam • Experimental investigation of low-energy induced SEU of 65 nm Bulk CMOS SRAM • Micro-beam irradiation technique & its applications • Proton & neutron irradiation technique in the near future
Location of CIAE South-western, 45 km from center of Beijing
7 Departments 8 Research Fields • Department of Nuclear Physics (200) • Department of Reactor Engineering and Technology • Department of Radiochemistry • Department of Nuclear Technology & Computer Application • Department of Radioisotope • Department of Radiation Safety • Department of Fast Reactor About 3000 permanent staffs
Radiation effect research lab (16) Single Event Effect (9) Radiobiological Effect (4) Facility operation & maintenance (2) Nuclear reaction and structure research lab Nuclear data measurement research lab Nuclear data evaluation research lab Accelerator operation & maintenance lab Neutron scattering research lab Nuclear technology application research lab Department of Nuclear Physics
What is Single Event Effect? • SINGLE-EVENT effects (SEE) in microelectronics are caused by highly charged energetic particles present in the natural space strike the sensitive regions of IC. • Depending on several factors, the particle strike may cause no observable effect, a transient disruption of circuit operation, a change of logic state, or even permanent damage to IC. • This effect is induced by only one particle, therefore it is called single-event effect
Single Event upset mechanism
Different mechanism for light and heavy ion Traditionally there are different SEE mechanism for light and heavy ions. Proton’s LET is not enough to generate SEU. But proton can induce nuclear reaction of Si. The products of nuclear reaction are much heavier than proton, they deposit higher charge density.
SEE is more severe in nm-scale technology • The critical charge decrease as the feature size decrease • Low-energy proton can induce SEU by direct ionization. • nuclear reaction with high z material • MBU induced by reaction is significantly increased. SEE induced by proton and neutron become a main reason to affect the reliability of ICs.
Description of Various Types ofSingle Event Effects in ICs Disturbance of an active electronic device caused by a single energetic particle • Upset (SEU) --change in logic state, simplest example is a memory cell in RAM • Latch-up (SEL) --sharp increase in current resulting from turning on parasitic pnpn • Damage or burn-out (SEB) of power transistor or other high voltage device • Functional interrupt (SEFI)- malfunctions in more complex parts sometimes as lockup, hard error, etc
Space Radiation Environment proton & heavy particle
Spaceflight Radiation Effect • The energy of these particles is so high that they can penetrate through spacecraft shell. The radiation effect of ICs used in spacecraft can affect the mission fulfillment of spacecraft and threaten its safety running three main radiation effects • Single-Event Effect • Total Ionization Dose • Displacement Damage Dose • SEE is the main effect among them. The sensitivity of SEE increases as the feature size of IC decreases.
The Near-Earth and Aviation Space Radiation Environment(mainly neutron and proton) There exist a lot of secondary particles resulting from the nuclear reaction between cosmic rays and atmosphere. In the plane height, about 90% is neutron. Secondary particle changes with flight altitude
SEE in atmosphere SEE induced by atmosphere neutron also affect the mission fulfillment of aero-craft and threaten its safety running
Ground simulation test • It is necessary that the ground simulation test based accelerator be carried out to evaluate the anti-SEE performance. • Accelerator can produce proton and heavy-ion. • It also used to produce quasi-mono-energetic neutron or white spectrum neutron.
The prediction of SEE rate in space • obtain threshold LET or E and the saturated cross section from the measured curve after weibull function fit. • Integrated with space radiation environment • Then error rate can be calculated (errors/day.bit) • Only the devices which ability of SEE hardening performance meets the requirement can be used in a specific space application. measure the curve of SEE cross section versus LET for heavy ion or E for proton & neutron
Chinese SEE sites (present and future) CIAE HI/p/n HIRFL, IMP, HI 300 MeV proton accelerator, mayby running in 2020 CSNS,1.6 GeV proton accelerator, produce neutron, running in 2017 200 MeV proton accelerator, dedicated for radiation effect, running in 2018
Institute of modern physics, Chinese academy of sciences SEE irradiation facility
Beam parameters at HIRFL • The energy of heavy ion is the highest in China, LET value ranges from 1~93 MeV.cm2/mg • Changing ion type is not convenient, it is often used to test SEL
HI-13 tandem accelerator • all of elements on the periodic table can be accelerated excepting inert gases. • Beam energy can be continuously adjusted and accurately controlled. • Ion type can be changed easy and rapidly. Photo of vessel for accelerated tube It is well suitable to carry out the SEE experiments. Especially, suitable to measure the curve of SEU cross section versus LET.
Beijing Nuclear physics Tandem accelerator laboratory(HI-13 tandem accelerator, terminal voltage:13 MV) stripper Beam energy E=Einj+(1+q)HV E=Einj+(1+0.25q1+0.75q2)HV Microbeam facility The present SEE facility Q3D, the former SEE facility
The beam allocation of HI-13 tandem accelerator Radiation physics: device & material Beam-time: 3~4:1 The beam time required for SEE has been increased sharply after 2006, the gap between the required and approved also goes larger and larger. Possible Solution • New accelerator • Increasing testing efficiency
1. Development of broad-beam irradiation facility dedicated for SEE Purpose: to test the performance of SEE and enhance test efficiency
Switching magnet facility Layout 1. Development of broad-beam irradiation facility dedicated for SEE Scanning frequency: 46/47 Hz Scanning magnet: 1600 Gs Two dimensional magnetic scanning method was used to produce a large and uniformly distributed beam. Simple Schematic diagram of broadening beam
Heavy ion SEE irradiation facility • DUT chamber size is 1100mm in diameter and 1100mm in height with a various of standard interfaces such as BNC,SHV, Sub D-9, D-15, D-25, D-50, et. al. • It have been put into use since the end of 2009 Photo of the irradiation facility
Beam diagnostic system • The beam uniformity and flux are monitored by a fixed monitor array which consists of four scintillation detectors and four FC. • The beam uniformity and flux are measured by a movable counter array which consists of 9-SD or 9-FC arranged in a square formation of 3-by-3 • K=NSD/NMON, ion number N=KNMON
Beam area is larger than 100mm100mm The non-uniformity over area of 50mm50mm is better than 5% Max beam area & distribution 2-D distribution of beam 1、scanning method up/down and left/right using 9-Si detector array
Beam distribution measured by plastic track detector Ion track distributions for 2 typical position (260m196m) The measured date of area 100mm100mm The non-uniformity over area of 100mm100mm is better than 6.8%
The adjustable ranges of beam flux • The ion beam flux can be changed via de-focus of Q and ion source • Si detector with collimator about 3,100-103ions/cm2.s with collimator about 1, 103-104ions/cm2.s • Plastic scintillation detector with collimator ,104-106ions/cm2.s • Faraday cup+pico-ampre, above 106 ions/cm2.s • Incident ion fluxes ranging from about 100 to 109 ions/cm2.s can be rapidly adjusted and accurately controlled within several minutes
Max irradiation area • Laser positioning system to ensure irradiation area via moving sample holder • Four test boards with a dimension of 254 mm 254 mm compatible with SEUTF at BNL and PIF at PSI can be installed on DUT holder simultaneously • As many as possible DUTs will be installed on the single test run. DUTs assembled in 3D structure
Fast vacuum technique 10-4 Pa • Large irradiation chamber • Many wires & cables • DUT change frequently • Pre-pumping by another pump • Optimized arrangement between pump and valve • Standard interface for cabling 10-2 Pa Venting time:3 min Pumping time: 6 min
Multi-users batch irradiation technique • Test efficiency has been enhanced sharply due to above techniques • For examples: test preparation: 2 days4 hr beam moderation:3hr 1 hr) • 4 times test per year, i.e., 1 times test averaged per season • 10~20 test runs per times, it means that 60~80 test runs per year. • 1~2 institutes per runs will perform their SEE test. • Beam time for each test run ranges from 10~20 hr
Chinese SEE Users • China Aerospace Science and Technology Corporation (spacecraft design) • China Electronics Technology Corporation (design & manufacture of IC) • Chinese Academy of Sciences (spacecraft application & SEE test) • China National Nuclear Corporation (SEE test) • University (effect mechanism ) • Commercial Enterprises (design & manufacture of IC) • From other countries • about 50 SEE units utilize our tandem accelerator
2. Application technique of highly stripping charge state ion beam Purpose: enhance the beam energy
The requirement for LET The LET needed to get SEU saturated cross section is continuous to increase.
Ions frequently used for SEE testing in the past at CIAE Beam energy of tandem is usually not high enough, especially for heavier elements such as Cu, Br and so on. For those elements, the projected ranges are lower than 30m.
Using highly charge state beam to increase beam energy; beam intensity become too weak to modulate Single stripper double stripper Beam energy E=Einj+(1+q)V single stripper E=Einj+(1+0.25q1+0.75q2)V double stripper
Pilot beam with the same magnetic rigidity is used to simulating the beam transmission for highly charge state ion
Simulation parameters for highly charge state 127I ion • Using 253.218 MeV127I14,21+(with a stripped probability of 1.89%) to get the operating voltage value VH; • Using 131.865 MeV127I14,21+(with a stripped probability of 1.98%) to simulating the optical route; • Then obtaining 318.843 MeV127I14,28+
Experimental layout Energy calibration of SDB Using SDA and SDB to detect incident beam
318 MeV127I (double carbon stripper) charge states:14,28 Stripping probability: 0.00536% Before optimization After optimization The ratio of the 318 MeV peak area to total area is more than 80% The peak intensity is around 2106 ions/s
360 MeV197Au (double carbon strippers) The ratio of the 360 MeVpeak area to total area is about 80% The peak intensity is around 1106ions/s
TYPICAL IONS FREQUENTLY USED FOR SEE TESTING AT CIAE The projected ranges in Silicon are more than 30 m for all ions of up to Gold. LET vs the penetrated depth
3. Experimental Investigation of SEU Induced by Low-Energy Proton on Commercial 65nm Bulk CMOS SRAM
Motivation • About 90% of particles in natural space radiation environment are proton, especially a majority of them are low-energy proton of less than 10 MeV • For nm SRAM, proton with an energy of about Bragg peak can generate enough charge through direct ionization to cause SEE • Therefore the cross section from direct ionization of low-energy proton is expected to be much higher than that from indirect ionization of secondary particle produced by nuclear reaction, since one of 1E5 proton can induce nuclear reaction. • Therefore the impact of low energy proton of SEE on Test methods and rate prediction is significant.
Irradiation facility Beijing HI-13 tandem accelerator at China Institute of Atomic Energy (CIAE) has been widely used for SEEs experiments since 1992. Heavy-ion irradiation facility dedicated for Single Event Effects (SEEs) test has been developed and put into use in 2009 [4]. Many institutes in China related to fundamental research and space application in the filed of SEEs are and will use this facility. Fig. 1 Heavy ion irradiation facility dedicated for SEEs testing at CIAE (Target chamber (T1, T2, T3, and T4), Magnet system (Q1 , DM, Q4, SM), Beam diagnoses system (FC1, FC2) , Slit (S), and Valve (V5, V6)
Test devices The experimental Device Under Test (DUT) is a commercial 65 nm 4M×18bit Bulk CMOS SRAM. The substrate thickness is about 200 micron. In order to suit the beam irradiation condition of HI-13 tandem accelerator, the device thickness from backside is thinned to about 50 micron. Fig. 2 Schematic of test system Fig. 3 Device Under Test (DUT)
Beam diagnostic method The beam uniformity and flux are measured by Si(Au) barrier semiconductor detectors (SD) and Faraday cups (FC). The FC are usually used in high flux testing such as proton-induced, while the SD are used in low beam flux testing such as low energy proton or heavy ion-induced SEE. Fig.4. Layout schematic diagram of the detector array for beam diagnostics(left: side view; right: front view)
Beam parameters The beam parameters used in this experiment are shown in Table I. The proton energy was varied from 7.4 to 15 MeV by changing the primary beam energy of tandem accelerator (Table 1). Fig.5 is the proton energy spectra. The 3.37 MeV proton deposited more energy than 8 MeV. Fig.5 Deposited energy spectra of 8 MeV proton (left: before degrader; right: after degrader)