ME-Pl
GATE RUPTURE OF OXIDE GROWN ON 6H-SÎC USING ION BEAM INDUCED CHARGE
Kin Kiong Lee1, T. Nishijima2, T. Oshima3, and David N. Jamieson1
1 Microanalytical Research Centre, School of Physics, University of Melbourne, Victoria 3010, AUSTRALIA
2 Quantum Radiation Division, Electrotechnical Laboratory, 1-1-4 Umezono, Tsukuba, Ibaraki, 305-858, JAPAN
3 Japan Atomic Energy Research Institute, Takasaki, Gunma 370-1292, JAPAN
Investigation of oxide charge trapping and interface state generation in SiO2 on 6H-SiC was performed using Ion Beam Induced Charge and the high frequency capacitance-voltage method. These trapped charges were related to the defects either existing in the oxide or generated during irradiation. Large flatband shift in capacitance-voltage measurements indicated that high density of positive charges are trapped near the interface of SiC/SiO2. The issue of oxide rupture caused by alpha particles on the metal-oxide-p-type SiC device will be addressed. The radiation hardness of SiC electronic devices will be reported.
ME-P2
INVESTIGATION OF THIN PHOSPHOR COATINGS ON PIN-DIODES BY IBICC/BBIL
C. Yang,2 B. L. Doyle," M. El Bouanani,3 B.N. Guo,a M. Nigam,3, J. L. Duggan," and F. D.
McDaniel"
a Ion Beam Modification and Analysis Laboratory, Department of Physics, University of North Texas, Denton, Texas 76203, USA
b Ion Beam Materials Research Laboratory, MS 1056, PO Box 5800, Sandia National Laboratories, Albuquerque, NM 87185, USA
A good-quality luminescent thin layer deposited on the top of microelectronic chips is required for the application of Ion Photon Emission Microscopy (IPEM) for microelectronics applications. Coatings of thin layers of phosphors on semiconductor devices have been investigated for the optimization of the luminescence efficiency and the homogeneity of the layers through the combined use of the techniques of Ion Beam Induced Charge Collection (IBICC) and Ion Beam Induced Luminescence (IBIL) in a nuclear microprobe. In search for a high efficiency of luminescence emission and a minimum layer thickness with a high homogeneity, the coatings of the different types of phosphors are produced by various deposition processes. The quantitative results are compared and discussed.
Acknowledgements :
The work is supported in part by NSF, the State of Texas Advanced Technology Program, and the Robert A. Welch Foundation.
ME-P3
MICROPROBE RBS ANALYSIS OF LOCALIZED PROCESSED AREAS BY FIB ETCHING AND DEPOSITION
R. Mimura. J. Tajima, T. Ochiai, Y.K. Park, and M. Takai
Research Center for Materials Science at Extreme Conditions and Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan
Impurity incorporation due to the localized beam processing by focused ion beams (FIBs) and electron beams (EBs) such as physical sputtering, gas-assisted etching (GAE) using iodine gas and beam-assisted deposition using [MeCpPt(Me)3] precursor gas has been investigated by a medium energy nuclear microprobe. RBS mapping on incorporated impurities has been performed using 300 keV beams with a beam spot size of 50 nm. RBS mapping images for physically sputtered and GAE areas indicate the localized Ga and I atoms distributions from the Ga FIB and from the etchant gas, respectively. The amount of Ga in the GAE area was estimated to be -2.7 times smaller than that in the physically sputtered area. RBS mapping images for FIB assisted Pt deposited areas revealed that Pt and Ga atoms distributed in the processed areas, while C atoms resided beyond the processed areas.
The analyzed results have been compared with those by EDS analysis using electron beam.
300keV Be2+ microprobe RBS analysis shows that iodine residues exist in the area of FIB assisted etching in iodine gas which cannot be detected by EDS analysis. It is confirmed that microprobe RBS analysis has higher sensitivity than EDS analysis.
ME-P4
INVESTIGATION OF SINGLE-EVENT CHARGE COLLECTION FROM ANGLED ION STRIKES
Hidenobu Moria. Toshio Hiraob, Shinobu Onodaa, Jamie Stuart Lairdb, Hisayoshi Itohb, Tsuyoshi Okamotoa, Yoshiharu Koizumf
a) Tokai University, 1117 Kitakaname, Hiratsuka, Kanagawa 259-1292, Japan,
b) Japan Atomic Energy Research Institute, 1233 Watanuki, Takasaki, Gunma 370-1292, Japan
Single event upset's (SEU) are a major in concern for DRAM and SRAM devices installed in space based satellites. Recently, large-scale integration of memory devices has made then even more susceptible to multiple-bit upsets (MBU). MBU generally results when an ion strike passes through, or interferes with, multiple memory cells at the same time. However, the fundamental processes behind MBU have not yet been fully clarified. In order to investigate MBU, we examined the relationship between the amount of collected charge and both the spatial position and the angle of the incident ion. The samples used in this experiment were Si pn junction diodes. The samples were irradiated with a variety of heavy ions and energies. Charge collection and transient current measurements were made as a function of the incident beam angle compared to TCAD simulation. Transient current measurements were made with the wide bandwidth oscilloscope system described elsewhere.
ME-P5
FRONTAL IBIC OF CdTe RADIATION DETECTORS AND RESPONSE TO LOW ENERGY GAMMA RAYS
Zeliko PASTUOVIC, Iva BOGDANOVIC RADOVIC and Milko JAKSlC, Department of Experimental Physics, Rudjer BoSkovic Institute, P.O.Box 180, 10002 Zagreb, Croatia Within a continuous international effort in developing the non-cryogenic semiconductor detectors for gamma ray spectroscopy, various wide gap materials were considered. With a best performance achieved, CdTe and CdZnTe based detectors became today widely accepted and commercially available. In addition to possible future use of such detectors for PIGE, nuclear microprobes are in recent years applied more as their characterisation tool using IBIC technique.
Several CdTe detectors of 2x2x1 mm3 size were used in this study. On the basis of frontal IBIC measurements of charge collection efficiency distribution, a spectral response to low energy gamma rays was simulated. These simulated spectra were compared with experimental peak shape measurements. Different modes of frontal IBIC (ions, energy) were used in order to find depth dependence of charge collection efficiency distribution. Further degradation of charge collection efficiency and the downward trend in peak position were studied by on-line irradiation of CdTe samples with 3 MeV protons up to 1010 p/cm2 radiation dose.
ME-P6
SINGLE ION INDUCED TRANSIENT MEASUREMENTS AND 3D SIMULATION OF PARTIALLY DEPLETED SOI
Harald Schone, Mike Hogsed, Air Force Research Lab, Albuquerque, NM 87117, USA, and Michael J. Hurt, Lockheed Martin, SE&C, Manassas, VA, USA
Electronic components built on Silicon on Insulator (SOI) have been part of the mainstream technology for space electronics for many years. The charge collection mechanisms for bulk or epitaxial CMOS components have been well researched in the past and are at this point well understood. The understanding of the charge collection mechanisms in fully or partly depleted SOI is still sketchy.
Our 3D, time dependent simulation results of single ion strikes through partially depleted SOI structure exhibit a suppressed charge collection volume for diffusive charge collection and a complete suppression of funneling assisted charge collection. The simulation results are substantiated through Time Resolved IBICC [1] measurements using 25 MeV carbon and copper ions at a position resolution of less than 1 micron. Furthermore, the results show a clear sensitivity of the charge collection on the ion strike location within a single FET and angle of ion incidence. It is also shown, that the parasitic bipolar effect induced by an ion strike can be significantly suppressed in partially depleted SOI by using properly designed body ties.
[1] H. Schone, F.W. Sexton, B.L. Doyle, D.S. Walsh, P.E. Dodd, R.S. Flores, J.F. Aurand, NIM B v.158, no. 1-4, p.424-31
ME-P7
METHOD BASED ON THE EXTENDED RAMO THEOREM TO INTERPRET CHARGE COLLECTION EFFICIENCY PROFILES AS DETERMINED BY LATERAL IBICC
E.Vittone1, F.Fizzotti1, C. Sanfilippo1, C.Manfredotti1, MJaksic2
!Exp. Physics Dept., University of Torino, INFN-To, INFM-UniTo, Italy
2Rudjer Boskovic Institute, Exp. Physics Dept., Zagreb, Croatia
An efficient method for calculating charge collection profiles in semiconductor devices as determined by lateral IBICC measurements is presented. The method is based on the extended Shockley-Ramo theorem that provides a rigorous mathematical tool for the calculation of the induced charge under the assumption of a quasi-steady state operation of the semiconductor device. The time dependent charge collection efficiency as a function of the ion impact distance from the electrodes is accomplished by calculating the current induced at the electrodes by the motion of the injected charges as evaluated using the weighting potential method.
The method turns out to be suitable to interpret lateral IBICC measurements (where funnelling effects are considered negligible) carried out on fully or partially depleted semiconductors, whichever is the contact quality of the electrodes (ohmic, injecting, blocking).
The method is applied to analyse charge collection efficiency profiles measured on virgin and damaged Si diodes with different doping profiles.
ME-P8
MICRO-EBICC AND MICRO-IL ANALYSIS OF CVD DIAMOND MICRODOSIMETERS
E.Vittone1. A.Lo Giudice1, C.Manfredotti1, G.Egeni2, V.Rudello2
'Exp. Physics Dept., University of Torino, INFN-To, INFM-UniTo, Italy
2INFN National Laboratory of Legnaro, Italy
Diamond is an ideal material to fabricate dosimeters because of its tissue equivalence, chemical stability, non-toxicity, mechanical and radiation hardness. Chemical vapour deposition technique (CVD) technique allows the fabrication of small diamond detectors, which can be considered for in vivo dose measurements. We have fabricated microdosimeters by depositing thin diamond films (<20 um thick) on tungsten wires ( 0 = 200 um). Such devices work as solid state ionisation chamber where the electrodes are the W substrate and a thin gold layer evaporated on the diamond surface. The ion beam induced charge collection (IBICC) and ionoluminescence (IL) techniques turn out to be very suitable to characterise such small and irregularly shaped microdosimeters. The uniformity of the electronic quality of diamond has been evaluated by mapping the charge collection efficiency as obtained by IBICC measurements, whereas IL was used to map radiative recombination centres as well as to study radiation damage effects in combination with the microRaman technique.