1、raising standards worldwideNO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBSI Standards PublicationSemiconductor devices Mobile ion tests for metal-oxidesemiconductor field effect transistors (MOSFETs)BS EN 62417:2010National forewordThis British Standard is the UK implementat
2、ion of EN 62417:2010. It is identical to IEC 62417:2010.The UK participation in its preparation was entrusted to Technical CommitteeEPL/47, Semiconductors.A list of organizations represented on this committee can be obtained onrequest to its secretary.This publication does not purport to include all
3、 the necessary provisions of acontract. Users are responsible for its correct application. BSI 2010ISBN 978 0 580 58622 4ICS 31.080.30Compliance with a British Standard cannot confer immunity fromlegal obligations.This British Standard was published under the authority of the StandardsPolicy and Str
4、ategy Committee on 30 June 2010.Amendments issued since publicationAmd. No. Date Text affectedBRITISH STANDARDBS EN 62417:2010EUROPEAN STANDARD EN 62417 NORME EUROPENNE EUROPISCHE NORM May 2010 CENELEC European Committee for Electrotechnical Standardization Comit Europen de Normalisation Electrotech
5、nique Europisches Komitee fr Elektrotechnische Normung Management Centre: Avenue Marnix 17, B - 1000 Brussels 2010 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members. Ref. No. EN 62417:2010 E ICS 31.080 English version Semiconductor devices - Mob
6、ile ion tests for metal-oxide semiconductor field effect transistors (MOSFETs) (IEC 62417:2010) Dispositifs semiconducteurs - Essais dions mobiles pour transistors semiconducteur oxyde mtallique effet de champ (MOSFET) (CEI 62417:2010) Halbleiterbauelemente - Prfverfahren auf mobile Ionen fr Feldeff
7、ekttransistoren mit Metall-Oxid-Halbleiter (MOSFET) (IEC 62417:2010) This European Standard was approved by CENELEC on 2010-05-01. CENELEC members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national s
8、tandard without any alteration. Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the Central Secretariat or to any CENELEC member. This European Standard exists in three official versions (English, French, German). A version in any
9、other language made by translation under the responsibility of a CENELEC member into its own language and notified to the Central Secretariat has the same status as the official versions. CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Croatia, Cyprus, the
10、 Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and the United Kingdom. BS EN 62417:2010EN 62417:2010 - 2 -
11、Foreword The text of document 47/2042/FDIS, future edition 1 of IEC 62417, prepared by IEC TC 47, Semiconductor devices, was submitted to the IEC-CENELEC parallel vote and was approved by CENELEC as EN 62417 on 2010-05-01. Attention is drawn to the possibility that some of the elements of this docum
12、ent may be the subject of patent rights. CEN and CENELEC shall not be held responsible for identifying any or all such patent rights. The following dates were fixed: latest date by which the EN has to be implemented at national level by publication of an identical national standard or by endorsement
13、 (dop) 2011-02-01 latest date by which the national standards conflicting with the EN have to be withdrawn (dow) 2013-05-01 _ Endorsement notice The text of the International Standard IEC 62417:2010 was approved by CENELEC as a European Standard without any modification. _ BS EN 62417:2010 2 62417 I
14、EC:2010 CONTENTS 1 Scope.5 2 Abbreviations and letter symbols 5 3 General description 5 4 Test equipment.6 5 Test structures .6 6 Sample size6 7 Conditions 6 8 Procedure 7 8.1 Bias temperature stress.7 8.2 Voltage sweep.7 9 Criteria .7 10 Reporting .8 BS EN 62417:201062417 IEC:2010 5 SEMICONDUCTOR D
15、EVICES MOBILE ION TESTS FOR METAL-OXIDE SEMICONDUCTOR FIELD EFFECT TRANSISTORS (MOSFETs) 1 Scope This present standard provides a wafer level test procedure to determine the amount of positive mobile charge in oxide layers in metal-oxide semiconductor field effect transistors. . It is applicable to
16、both active and parasitic field effect transistors. The mobile charge can cause degradation of microelectronic devices, e.g. by shifting the threshold voltage of MOSFETs or by inversion of the base in bipolar transistors. 2 Abbreviations and letter symbols This standard uses the following abbreviati
17、ons and letter symbols: CV test capacitance-voltage measurement HFCV test high frequency capacitance-voltage measurement Vggate voltage toxoxide thickness Idsdrain-source current Vddpositive power supply voltage Vdd,maxmaximum supply voltage Vttransistor threshold voltage Vt,initialthe absolute valu
18、e of the threshold voltage before the test Vsupplythe absolute value of the supply voltage oxdielectric constant of the oxide 3 General description The stress applied is on test structures at an elevated temperature where mobile ions can overcome the energy barriers at the interfaces and the ion mob
19、ility in the oxide is sufficiently high. Two test methods are described in this document. Bias temperature stress (BTS) Voltage sweep (VS). The bias temperature stress test is done on transistors. The threshold voltage is determined from an Ids- Vgsmeasurement at room temperature on fresh structures
20、. The threshold voltage is defined as the gate voltage needed to force a fixed drain current through the transistor. Then, a positive gate stress is applied at a high temperature, to sweep the mobile ions towards the substrate. After the stress the test structure is cooled to room temperature with t
21、he bias still applied. A second Ids- Vgscurve is measured at room temperature. The sequence is completed with a negative gate stress at high temperature followed by an Ids- Vgsmeasurement at room temperature. Mobile charge causes a shift in the Ids- Vgscurve. The distance over which the curve is shi
22、fted is a measure of the amount of mobile charge in the insulator. BS EN 62417:2010 6 62417 IEC:2010 Edge effects of the transistor structure can be taken into account by applying a negative gate bias for 2 minutes duration at the elevated temperature prior to the BTS measurement. NOTE Mobile charge
23、 in dielectric layers above a large area polysilicon or metal-plate cannot be detected, because there is no electric field which drives the ions towards the underlying oxide. To overcome this problem special edge sensitive test structures can be used, that have a large edge/area value, e.g. structur
24、es with fingers. The voltage sweep measurements are done on capacitors. A quasi-static C-V curve is measured and compared with a low-frequency C-V curve. The ionic displacement current, which appears as a peak in the quasi-static C-V curve, is indicative of the mobile ion concentration. 4 Test equip
25、ment The hot chuck shall be capable of maintaining a temperature of 250 C. A capacitance (LCR) meter is needed for HFCV measurements and quasi-static C-V measurements. A pA-meter is needed for low-frequency C-V (typical frequency = 1 kHz) measurements. The frequency for low-frequency C-V measurement
26、s may differ from 1 kHz as long as the accumulation and inversion capacitances differ no more than 10 %. 5 Test structures The test structures for bias temperature stress are transistors and, for voltage sweep, capacitors are used. The minimum area Aminof this capacitor is calculated from the voltag
27、e sweep rate dV/dt and the lowest measurable current Imin(determined by the resolution of the test equipment) according to the following equation: tVtIAoxoxd/d0minmin=(1) where 0is the permittivity of vacuum. 6 Sample size The recommended sample size is 5. 7 Conditions The electric field during stre
28、ss is as follows: 1,0 MV/cm with a minimum of (operating voltage +10 %) for gate oxide; 0,2 MV/cm for polysilicon gates on field oxide; 0,3 MV/cm for metal gates on field oxide. The electric field is calculated as Vg/tox. BS EN 62417:201062417 IEC:2010 7 8 Procedure 8.1 Bias temperature stress The t
29、est structures are subsequently subjected to the following procedures: measure the first Ids- Vgs(or HFCV) characteristic at room temperature; apply a positive gate bias to collect mobile ions at the silicon/oxide interface; ramp the temperature to 250 C; hold 5 min; ramp down to room temperature; r
30、emove bias; measure the second Ids- Vgs(or HFCV) characteristic; apply a negative gate bias to collect mobile ions at the gate/oxide interface; ramp the temperature to 250 C; hold 5 min; ramp down to room temperature; remove bias; measure the third Ids- Vgs(or HFCV) characteristic. Ids- Vgscharacter
31、istics may be measured at 250 C (fast tests). HFCV and Ids- Vgsmeasurements shall be started with the polarity used in the preceding high temperature stress. NOTE Reporting of correlation data is required if the stress temperature deviates from 250 C by more than 10 C. 8.2 Voltage sweep The device t
32、emperature is 250 C. The start/stop values of the gate bias are calculated from the oxide thickness, so that the maximum electric field is 1 MV/cm. The stress field is 1 MV/cm. The capacitors are subsequently subjected to a positive gate stress of 1 MV/cm for 5 seconds duration to collect mobile ion
33、s at the silicon/oxide interface, a low-frequency C-V measurement, a positive gate stress of 1 MV/cm for a period of 20 s, a quasi-static C-V measurement with a negative gate voltage ramp of 100 mV/s. The electric field is defined as Vg/tox. For thick oxides the electric field is limited by the supp
34、ly voltage of the equipment. The values for the stress field and the start/stop values may then be reduced, but shall be at least 2 105V/cm. NOTE Reporting of correlation data is required if the temperature deviates from 250 C by more than 10 C. 9 Criteria The shift in the threshold voltage shall be
35、 less than 0,02 Vdd,maxwith a minimum value of 100 mV for gate oxides, where Vdd,max is the maximum voltage difference between Vddpins and ground; BS EN 62417:2010 8 62417 IEC:2010 Vt,initial 1,5 Vsupplyfor polysilicon and metal gates on field oxide, where Vt,initialis the absolute value of the thre
36、shold voltage before the test, and Vsupplyis the absolute value of the supply voltage. If Vt,initial 1,5 Vsupply 0, then the shift shall be less than Vdd/10. Typical values for the observed shifts are less than 10 mV for gate oxides, less than 1 V for polysilicon gates on field oxide, and less than
37、3 V for metal gates on field oxides. If I/O-pins are subjected to a voltage higher than the supply voltage in any production components, then this value shall be used to determine the maximum shift for field oxide structures. For bias temperature stress the shift in the threshold voltage in the seco
38、nd and third Ids- Vgswith respect to the first Ids- Vgscurve (or the shift of the flat band voltage for capacitor measurements) shall be less than the maximum allowed threshold voltage shift defined above. For voltage sweep the maximum allowed mobile ion density (in cm2) can be calculated from oxoxt
39、qVN=t0max(2) where Vtis the maximum threshold voltage shift defined above, and 0is the permittivity of vacuum. The mobile ion density is given by Nm= Qm/(Axq), where q is the elementary electronic charge, and A is the area of the capacitor. The total amount of mobile charge Qmin the insulator equals
40、 the area of the peak in the quasi-static C-V curve. This area is found by subtracting the low-frequency C-V curve from the quasi-static C-V curve. 10 Reporting The sample size, the maximum allowed threshold voltage shift, the test results and any deviations from the given conditions shall be report
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