1、BSI Standards PublicationNuclear instrumentation High-purity germanium crystals for radiation detectors Measurement methods of basic characteristicsBS IEC 61435:2013National forewordThis British Standard is the UK implementation of IEC 61435:2013.The UK participation in its preparation was entrusted
2、 to TechnicalCommittee NCE/2, Radiation protection and measurement.A list of organizations represented on this committee can be obtained onrequest to its secretary.This publication does not purport to include all the necessary provisions ofa contract. Users are responsible for its correct applicatio
3、n. The British Standards Institution 2013.Published by BSI Standards Limited 2013ISBN 978 0 580 76224 6ICS 27.120Compliance with a British Standard cannot confer immunity fromlegal obligations.This British Standard was published under the authority of theStandards Policy and Strategy Committee on 31
4、 August 2013.Amendments issued since publicationDate Text affectedBRITISH STANDARDBS IEC 61435:2013IEC 61435 Edition 2.0 2013-08 INTERNATIONAL STANDARD Nuclear instrumentation High-purity germanium crystals for radiation detectors Measurement methods of basic characteristics INTERNATIONAL ELECTROTEC
5、HNICAL COMMISSION V ICS 27.120 PRICE CODE ISBN 978-2-8322-1033-8 Registered trademark of the International Electrotechnical Commission Warning! Make sure that you obtained this publication from an authorized distributor. BS IEC 61435:2013 2 61435 IEC:2013(E) CONTENTS FOREWORD . 4 INTRODUCTION . 6 1
6、Scope and object 7 2 Normative references . 7 3 Terms, definitions, symbols and abbreviations 7 3.1 Terms and definitions 7 3.2 Symbols and abbreviations 9 Symbols 9 3.2.1Abbreviations 10 3.2.23.3 Quantities and units 10 4 Measurement of net electrically-active impurity concentrations . 10 4.1 Sampl
7、e preparation for Van der Pauw measurements 10 General . 10 4.1.1Equipment . 11 4.1.2Dimensions and provisions for contacts . 11 4.1.3Etching 12 4.1.44.2 Measurements of (NA ND) 13 General . 13 4.2.1Equipment . 13 4.2.2Measurements of resistivity . 14 4.2.3Measurements of Hall coefficient . 14 4.2.4
8、Calculation of (NA ND) from resistivity . 15 4.2.5Calculation of drift mobility from a Van der Pauw measurement . 15 4.2.6Computation of (NA ND) from RH16 4.2.7Spatial dependence of (NA ND) . 17 4.2.8Axial variations in (NA ND) 18 4.2.95 Deep level transient spectroscopy for the determination of imp
9、urity-centre concentration 18 5.1 General . 18 5.2 Equipment for DLTS method 18 5.3 Sample selection and preparation for DLTS . 19 5.4 Measurements for the determination of impurity-centre concentration 19 General . 19 5.4.1DLTS signal as a function of temperature 21 5.4.2Calculation of (NA ND) 21 5
10、.4.3Corrections for equivalent circuit effects 21 5.4.4Corrections for high trap concentrations and for voltage pulse height 23 5.4.5pcVVtechnique for measuring NT23 5.4.65.5 Majority-carrier deep levels in p-type HPGe . 24 5.6 Majority-carrier deep levels in n-type HPGe . 25 5.7 Report . 26 6 Cryst
11、allographic properties . 26 6.1 General . 26 6.2 Crystallographic orientation . 26 6.3 Sample preparation . 26 BS IEC 61435:201361435 IEC:2013(E) 3 General . 26 6.3.1Preferential etching . 26 6.3.2Etching methods 27 6.3.3Etch-pit density 27 6.3.4Lineage . 27 6.3.5Mosaic . 27 6.3.66.4 Report . 27 Ann
12、ex A (informative) The Hall factor for n-type and p-type HPGe . 28 Annex B (informative) Function DABC,D,RRf versus DABC,CDAB,RR30 Bibliography 31 Figure 1 Samples . 12 Figure 2 Examples of sample shapes . 18 Figure 3 DLTS waveforms and gate timing . 20 Figure 4 pcVVwaveforms . 24 Figure A.1 Hall fa
13、ctor for n-type HPGe . 28 Figure A.2 Hall factor for p-type HPGe . 29 Figure B.1 Function DABC,D,RRf versus DABC,CDAB,RR21 30 Table 1 Majority-carrier deep levels in p-type HPGe 25 BS IEC 61435:2013 4 61435 IEC:2013(E) INTERNATIONAL ELECTROTECHNICAL COMMISSION _ NUCLEAR INSTRUMENTATION HIGH-PURITY G
14、ERMANIUM CRYSTALS FOR RADIATION DETECTORS MEASUREMENT METHODS OF BASIC CHARACTERISTICS FOREWORD 1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising all national electrotechnical committees (IEC National Committees). The object of IEC is t
15、o promote international co-operation on all questions concerning standardization in the electrical and electronic fields. To this end and in addition to other activities, IEC publishes International Standards, Technical Specifications, Technical Reports, Publicly Available Specifications (PAS) and G
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23、or indirect, or for costs (including legal fees) and expenses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC Publications. 8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is indispensable
24、 for the correct application of this publication. 9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of patent rights. IEC shall not be held responsible for identifying any or all such patent rights. International Standard IEC 61435 has been
25、 prepared by IEC technical committee 45: Nuclear instrumentation. This second edition cancels and replaces the first edition published in 1996 and constitutes a technical revision. The main technical changes with regard to the previous edition are as follows: Review the existing requirements. Update
26、 the terminology and definitions. The text of this standard is based on the following documents: FDIS Report on voting 45/754/FDIS 45/760/RVD BS IEC 61435:201361435 IEC:2013(E) 5 Full information on the voting for the approval of this standard can be found in the report on voting indicated in the ab
27、ove table. This publication has been drafted in accordance with the ISO/IEC Directives, Part 2. The committee has decided that the contents of this publication will remain unchanged until the stability date indicated on the IEC web site under “http:/webstore.iec.ch“ in the data related to the specif
28、ic publication. At this date, the publication will be reconfirmed, withdrawn, replaced by a revised edition, or amended. A bilingual version of this publication may be issued at a later date. BS IEC 61435:2013 6 61435 IEC:2013(E) INTRODUCTION Detector manufacturers demand numerical data that can be
29、used to predict the performance of a detector having approximately coaxial geometry. However, because of the many variations in the physical characteristics, the completed detector performance cannot be fully predicted from measurements of the crystal manufacturer. This standard defines terminology
30、and test methods for determining basic crystal parameters such as net electrically active impurity concentrations, deep-level impurity-centre concentration and crystallographic quality of crystals. Production of germanium crystals of the necessary size and defined purity for high-purity germanium (H
31、PGe) detectors for detection of ionizing radiation has special problems in characterization resulting from the high resistivity of the material (10 kcm at 77 K), from the degree of impurity compensation, and from difficulties in suitably describing the impurity distribution in the large volume that
32、may form a single device. Existing standards do not cover these problems. One of the most important characteristics of HPGe is the net electrically active impurity concentration (NA ND) because it determines the depletion voltage required for an operating detector. The usual practice has been to det
33、ermine (NA ND), with the sign indicating n-type or p-type, on the basis of transport measurements using the Van der Pauw method 11on lamellar samples immersed in liquid nitrogen (LN). In this technique, (NA ND) can be computed either from the resistivity or from the Hall coefficient. These in turn a
34、re obtained from a series of electrical measurements made on the sample. _ 1Numbers in square brackets refer to the Bibliography. BS IEC 61435:201361435 IEC:2013(E) 7 NUCLEAR INSTRUMENTATION HIGH-PURITY GERMANIUM CRYSTALS FOR RADIATION DETECTORS MEASUREMENT METHODS OF BASIC CHARACTERISTICS 1 Scope a
35、nd object This International Standard is applicable to high-purity germanium crystals used for radiation detectors for gamma-rays and X-rays. Such germanium is monocrystalline and has a net concentration of fewer than 1011electrically active impurity centers per cm3, usually of the order of 1010cm3.
36、 This International Standard specifies terminology and test methods for measurements of basic characteristics of high-purity germanium crystals. These characteristics are net electrically active impurity concentrations (hereinafter (NA ND), deep-level impurity-centre concentration and crystallograph
37、ic quality of crystals. These test methods are not mandatory but have found general use in the industry and provide verifiable and desired information to the detector manufacturer. Test methods for completed assembled germanium detectors are given in IEC 60973 and IEC 60759. 2 Normative references T
38、he following documents, in whole or in part, are normatively referenced in this document and are indispensable for its application. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. IEC 6000
39、50-393:2003, International Electrotechnical Vocabulary (IEV) Part 393: Nuclear instrumentation Physical phenomena and basic concepts IEC 60050-394:2007, International Electrotechnical Vocabulary (IEV) Part 394: Nuclear instrumentation Instruments, systems, equipment, and detectors IEC 60050-521:2002
40、, International Electrotechnical Vocabulary (IEV) Part 521: Semiconductor devices and integrated circuits 3 Terms, definitions, symbols and abbreviations 3.1 Terms and definitions For the purposes of this document, the following terms and definitions apply. 3.1.1semiconductor substance whose total c
41、onductivity due to charge carriers of both signs is normally in the range between that of conductors and insulators and in which the charge carrier density can be changed by external means Note 1 to entry: The term semiconductor generally applies where the charge carriers are electrons or holes. SOU
42、RCE: IEC 60050-521:2002, 521-02-01 BS IEC 61435:2013 8 61435 IEC:2013(E) SOURCE: IEC 60050-394:2007, 394-28-33 3.1.2high purity semiconductor detector semiconductor detector using a high purity (e.g. high resistivity) semiconductor material SOURCE: IEC 60050-394:2007, 394-28-14 3.1.3Hall effect prod
43、uction in a conductor or in a semiconductor of an electric field strength proportional to the vector product of the current density and the magnetic flux density SOURCE: IEC 60050-521:2002, 521-09-01 3.1.4Hall mobility product of the Hall coefficient and the electric conductivity SOURCE: IEC 60050-5
44、21:2002, 521-09-02 3.1.5Hall coefficient coefficient of proportionality RHin the Hall effect quantitative relation: )(HHBJRE= HEis the resulting transverse electric field strength; Jis the current density; Bis the magnetic flux density. Note 1 to entry: The sign of the majority carrier charge can us
45、ually be inferred from the sign of the Hall coefficient. SOURCE: IEC 60050-521:2002, 521-09-02 3.1.6mobility drift mobility of a charge carrier quantity equal to the quotient of the modulus of the mean velocity of a charge carrier in the direction of an electric field by the modulus of the field str
46、ength SOURCE: IEC 60050-521:2002, 521-02-58 3.1.7impurity foreign atoms or either an excess or a deficiency of atoms with respect to the stochiometric composition of a compound semiconductor SOURCE: IEC 60050-521:2002, 521-02-04 3.1.8resistivity inverse of the conductivity when this inverse exists B
47、S IEC 61435:201361435 IEC:2013(E) 9 SOURCE: IEC 60050-121:1998, 121-12-04 3.2 Symbols and abbreviations Symbols 3.2.1Frequently used symbols are defined below; infrequently used symbols are defined in the text. A diode area, expressed in cm2; B magnetic flux density, expressed in teslas (T); C capac
48、itance, expressed in farads (F); Cdcapacitance of the depleted region in a diode; Ciinitial capacitance; Cfcapacitance at voltage Vr; Cmthe capacitance of parallel equivalent circuit; Dsthe series circuit dissipation factor;D Sample thickness, expressed in centimetres (cm); e electron charge, 1,60 1
49、019coulombs (C); ercarrier emission rate from a localized electronic level, expressed in s1; E energy associated with an electronic level in the band gap; F frequency, expressed in hertz (Hz); f is a factor dependent on ratio DABC,CDAB,RR; K Boltzmann constant, 8,617 105eVK1; (NA ND)net electrically active impurity concentration per cm3; NTdeep-level impurity-centre concentration per
