ESD與TCADSilvaco仿真(浙江大學(xué))

1、esd與tcad仿真報(bào)告人：浙大微電子 崔強(qiáng)email: 共163頁(yè)2welcome! 熱烈歡迎各位參加本次講座的學(xué)員。由于本人水平有限，在座的各位如果有什么問(wèn)題，請(qǐng)立刻打斷我。共163頁(yè)3welcome!本次講座分3個(gè)小節(jié)，中途有兩次休息，歡迎大家和我探討。1. 單元1：tcad簡(jiǎn)介2. 單元2：esd的tcad仿真簡(jiǎn)介3. 單元3：esd的仿真評(píng)價(jià)體系共163頁(yè)4單元1 1.1：tcad總體簡(jiǎn)介 1.2：tsuprem4/medici 1.3：athena/atlas 1.4：dios/ dessis （ise-tcad）共163頁(yè)51.1：tcad總體簡(jiǎn)介tcadtechnology c

2、omputer aided designtsuprem/medici（avanti，被synopsys收購(gòu)）athena/atlas（silvaco公司）dios/dessis（ise公司，被synopsys 收購(gòu)）共163頁(yè)61.2：tsuprem4/medici tsuprem4/medici是avanti公司的二維工藝、器件仿真集成軟件包。tsuprem4是對(duì)應(yīng)的工藝仿真軟件，medici是器件仿真軟件。在實(shí)踐中，可以將tsuprem4的工藝仿真的結(jié)果導(dǎo)入到medici中，從而進(jìn)行較為精確的仿真。共163頁(yè)71.2 .1：tsuprem4capabilitiestsuprem-4 sim

3、ulates silicon ic process fabrication1.ion implantation2.epitaxial growth3.diffusion4.oxidation of silicon and polysilicon5.etching and deposition6.silicidation of silicon and polysilicon共163頁(yè)8 specifications1.two-dimensional2.supports up to 40,000 nodes3.written in c共163頁(yè)9 command input language th

4、e input language is made up of commands and corresponding parameters1.there is only one command per line2.the line can be up to 80 characters long. if it s longer, we can continue in the next line, but the last character in the previous line must be a “+” character.共163頁(yè)10types of commandsthere are

5、two types of commands1. declaration (used to set parameters)2. action (execution used to perform a process step)共163頁(yè)11parameters there are three types of parameters1. numerical (e.g. temp=1000)2. logical (e.g. clear)3. character (e.g. “nmos3a”)共163頁(yè)12files associated with running tsuprem-4 simulati

6、ons1. input file (*.inp)2. output file (*.out appended automatically by program)3. tsuprem-4 structure file (*.str)4. medici/davinci file (*.dev)5. universal (tif) format file (*.tif)共163頁(yè)13create a simulation1. setting up the initial grid2. models and coefficients (method)3. process statements (dep

7、osition, expose, develop, etch, implant, diffusion, epitaxy)4. electrical calculations in tsuprem-45. extracting results (non-electrical) from tsuprem-4共163頁(yè)141.2 .2：medici features：medici solves poissons equation and the current continuity of electrons and holes in two dimensionsthese equations can

8、 be extended to include the heat equation and the energy-balance equationsthe following modes of analysis can be considered: dc, ac, transient共163頁(yè)15 doping and structure information can either be input from a process simulator e.g. tsuprem4 or generated within medici a wide range of mobility and re

9、combination/generation models available output to parameter extraction programs such as aurora possible共163頁(yè)16 full post processing capabilities including plotting internal quantities, terminal characteristics extract capability makes calculations with a wide range of parameters possible for pre and

10、 post processing solutions. a target parameter can be identified for optimization共163頁(yè)17advanced application modules1. lattice temperature aam solves the heat equation2. optical device aam enhanced radiation effects, ray tracing3. heterojunction device aam conduction across a material boundary with

11、discontinuous energy gap共163頁(yè)184.programmable device aam allows a charge boundary condition on a floating electrode5.circuit analysis aam allows devices to be treated as circuit elements in a spice type circuit6.anisotropic device aam allows anisotropic material parameters useful in the treatment of

12、 sic type applications共163頁(yè)19meshinitiates a mesh and must appear first when defining a structure.x.meshy.mesheliminateused to specify exact locations of mesh lines produces a rectangular grid which can be reduced in density by using eliminate to remove excess nodes away from area of interestcreate

13、a simulation共163頁(yè)20spreadboundaryolder statements whose function is no longer so necessary. spread allows the creation of a locos shaped structure on a rectangular mesh and boundary allows a set of coordinates to be input to define a regions topography.共163頁(yè)21tsuprem4used to transfer surface feature

14、s and doping profiles from tsuprem4 onto an existing medici meshstitchnew command to allow multiple tsuprem4 files to be usedregionused to define regional properties where no material data already exists共163頁(yè)22electrodeadds location of electrodes to structurerenamerenames electrodes or regionsprofil

15、eallows addition of doping information either by creating simple profiles or inputting from a process simulatorregridallows regridding of mesh based on some internalquantities共163頁(yè)23 some statementsregrid statement the regrid statement can be used to refine a grid for greater accuracy.1. specify qua

16、ntity to be used e.g potential, electric field, min.carr2. refinement criterium e.g ratio=2 “regrid doping log ratio=2 in.file=test.dop + smooth=1”共163頁(yè)24 rename electrodes when electrodes are transferred from tsuprem-4 to medici, they will be numbered sequentially. it is often convenient to rename

17、them with names easier to remember. “rename electrode oldname=1 newname=source rename electrode oldname=2 newname=drain”共163頁(yè)25 models the physics is selected on the model statement. this is supported by a mobility statement and a material statement which allow default parameters for the mobility an

18、d other models to be altered within specified regions or materials.共163頁(yè)26 the models that can be selected can broadly be divided into the following categories:1.recombination and generation models2.mobility modeling3.models affecting relation between carrier density and electric field. i.e bandgap

19、narrowing, fermi-dirac or boltzmann statistics, quantum mechanical4.energy balance modeling共163頁(yè)27modeldesciptionsrhshockley read hallconsrhsrh + concentration dependant lifetimesaugerauger recombinationr.tunnelsrh including tunnelling in presence of strong electric filedsimpact.iclassic chynoweth e

20、xpressionii.tempinvokes a temperature based version of the impact ionization model for use with the energy balance modelrecombination and generation models共163頁(yè)28modellow fieldtransverse fieldparallel fieldcommentsccsmobcarrier-carrier scatteringconmobconcentration dependence from tables 300kanalyti

21、canalytic alternative to conmob with temp dependencephumobcarrier-carrier scattering, different donor and accetor scattering, screening, useful for bipolarsmobility models共163頁(yè)29modellow fieldtransverse fieldparallel fieldcommentslsmmostreats surface scattering and bulk effectsgmcmobmodified lsmmob

22、to include screened and unscreened impurity scatteringmobility models共163頁(yè)30modellow fieldtransverse fieldparallel fieldcommentssrfmobbasic and enhanced model for surface scattering.requires vertical grid spacing inversion layersrfmob2unimobneeds rectangular grid in inversion layer models surface sc

23、atteringprpmobgeneral model for degradation of mobility with transverse electric field mobility models共163頁(yè)31modellow fieldtransverse fieldparallel fieldcommentstfldmobuniv texas mobility modelfldmobcarrier heating and velocity saturation effectshpmobaccounts for both parallel and perpendicular fiel

24、d dependencemobility models共163頁(yè)32modeldescriptionfermidirfermi dirac statistics instead of boltzmann.incompleincomplete ionization of impuritiesbgnbandgap narrowing modeling especially important for bipolarsqm.philiaccounts for quantum mechanical effects in mosfet inversion layers using van dorts b

25、andgap widening model.other models共163頁(yè)33 boundary conditions the standard boundary conditions are that the normal component of the electric field and the current densities disappear at the boundaries (neumann boundary conditions) except at the electrodes where fixed conditions can be ascribed (diri

26、chlet conditions). variations in those conditions can be applied using the contact statement and the interface statement can be used to input discontinuities at material boundaries.共163頁(yè)34 contact statement the default conditions are that ohmic conditions applied and the electrostatic potential equa

27、ls the applied voltage. the carrier densities are then calculated from the space charge neutrality relation. “ contact name=gate workfunction=4.35 comment (defaul unit: ev) contact name=base current”共163頁(yè)35 solution technique in order to obtain the solution we essentially have to decide on two thing

28、s.1. select equations to be solved2. decide how to bias our structure statements which fall into this group are symbolic, method, solve.共163頁(yè)36symbolic statement1. poissons equation2. electron current-continuity equation3. hole current continuity equation4. lattice temperature (heat) equation5. elec

29、tron energy-balance equation6. hole energy-balance equation共163頁(yè)37共163頁(yè)38 what to do when the folloing message appears on the screen?“ error number 166 detected in line number xx. more than 4 solutions failed to converge. execution terminated! ”共163頁(yè)39 the primary causes of non convergence are:1. po

30、or initial guess bias step too large2. lack of necessary physical models3. poor simulation grid4. depletion layer touching the electrode共163頁(yè)401.3：athena/atlas tsuprem4/medici是avanti公司的二維工藝、器件仿真集成軟件包。tsuprem4是對(duì)應(yīng)的工藝仿真軟件，medici是器件仿真軟件。在實(shí)踐中，可以將tsuprem4的工藝仿真的結(jié)果導(dǎo)入到medici中，從而進(jìn)行較為精確的仿真。共163頁(yè)411.3.1：athenan

31、登錄界面共163頁(yè)42ngui 方式設(shè)定網(wǎng)格共163頁(yè)43n編程方式設(shè)定網(wǎng)格共163頁(yè)44n定義初始襯底共163頁(yè)45n柵極氧化共163頁(yè)46共163頁(yè)47n離子注入共163頁(yè)48n多晶硅柵的淀積共163頁(yè)49共163頁(yè)50n幾何刻蝕共163頁(yè)51共163頁(yè)52 n多晶硅氧化 “method fermi compress”共163頁(yè)53共163頁(yè)54#polysilicon dopingimplant phosphor dose=3e13 energy=20 crystaln多晶硅摻雜共163頁(yè)55共163頁(yè)56n氧化層淀積和側(cè)墻氧化隔離共163頁(yè)57“#source/drain implan

32、timplant arsenic dose=5e15 energy=50 crytal#source/drain annealingmethod fermidiffus time=1 temp=900 nitro press=1.00”n源/漏極注入和退火共163頁(yè)58共163頁(yè)59“#open contact window etch oxide left p1.x=0.2”n氧化物的刻蝕和金屬的淀積刻蝕共163頁(yè)60共163頁(yè)61“#aluminum deposition deposit aluminum thick=0.03 divisions=2；”共163頁(yè)62共163頁(yè)63“#etc

33、h aluminum etch aluminum right p1.x=0.18”共163頁(yè)64共163頁(yè)65n半個(gè)nmos結(jié)構(gòu)的鏡像共163頁(yè)66n電極的確定 和保存athena結(jié)構(gòu)文件共163頁(yè)67 “electrode name=source x=0.1 electrode name=drain x=1.1 electrode name=gate x=0.6”共163頁(yè)681.3.2：atlas共163頁(yè)69 n登錄界面共163頁(yè)70n導(dǎo)入athena結(jié)構(gòu)共163頁(yè)71n模型命令組共163頁(yè)72ncategory欄中選擇recombination選項(xiàng) 共163頁(yè)73n數(shù)字求解方法命令組共

34、163頁(yè)74n解決方案命令共163頁(yè)75ntonyplot繪出idvds特性曲線族 共163頁(yè)761.4：dios/ dessis 工藝及器件仿真工具ise-tcad（tcad：technology computer aided design）是瑞士 ise ( integrated systems engineering ) 公司開(kāi)發(fā)的dfm（design for manufacturing）軟件，是一種建立在物理基礎(chǔ)上的數(shù)值仿真工具，它既可以進(jìn)行工藝流程的仿真、器件的描述，也可以進(jìn)行器件仿真、電路性能仿真以及電缺陷仿真等。共163頁(yè)771.4.1： dios dios簡(jiǎn)介簡(jiǎn)介 dios輸入

35、文件是由一系列連續(xù)執(zhí)行的命令構(gòu)成。dios輸入文件的后綴及擴(kuò)展名為：“_dio.cmd”。dios的輸入語(yǔ)言并不區(qū)分字母的大小寫(xiě)。不過(guò)，文件名和電極觸點(diǎn)名是區(qū)分大小寫(xiě)的。共163頁(yè)78 一個(gè)典型的dios文件一般以初始化的命令開(kāi)始，并且初始化命令不可以省略。例如： title(.)grid(.)substrate(.)共163頁(yè)79 之后，可以根據(jù)需要選擇性地添加仿真命令語(yǔ)句，如：mask(.)implant(.)diffusion(.)deposit(.)etching(.)共163頁(yè)80 在完成了這些仿真語(yǔ)句之后，可以用：1d(.)save(.)命令對(duì)仿真結(jié)果進(jìn)行保存。用“end”命令作為

36、整個(gè)文件的結(jié)束。共163頁(yè)81title(.)” 命令命令該命令總是出現(xiàn)在dios輸入文件的最開(kāi)始的地方，用來(lái)對(duì)仿真進(jìn)行初始化。例如：title(simple nmos example)這條指令對(duì)仿真進(jìn)行了初始化，并且把圖形窗口命名為“simple nmos example”。title(test, sidiff=off, newdiff=1)該命令同樣也是對(duì)仿真進(jìn)行初始化，并把圖形窗口命名為“test”，同時(shí)，sidiff=off表示僅在除硅以外的層次擴(kuò)散，比如氧化層和多晶硅，以節(jié)約仿真時(shí)間。newdiff=1表示所有層次都定義網(wǎng)格和摻雜，n各種命令說(shuō)明共163頁(yè)82 grid(.)”命令命

37、令網(wǎng)格命令一般跟在“title”命令之后，它是用來(lái)定義器件結(jié)構(gòu)初始化網(wǎng)格的，同時(shí)也包括了器件的橫向和縱向范圍。在默認(rèn)的情況下，dios在每一步仿真之后都會(huì)對(duì)網(wǎng)格進(jìn)行重新編制，這樣可以解決在制做工藝中幾何尺寸和摻雜濃度改變而引起的問(wèn)題。如果說(shuō)沒(méi)有明確指定網(wǎng)格調(diào)整參數(shù)，那么dios將會(huì)通過(guò)自己默認(rèn)的調(diào)整標(biāo)準(zhǔn)對(duì)網(wǎng)格進(jìn)行調(diào)整。例如： grid (x (0.0, 0.4), y (-10.0, 0.0), nx=2)在該命令中沒(méi)有對(duì)網(wǎng)格的調(diào)整標(biāo)準(zhǔn)。它對(duì)器件橫向范圍從0um到0.4um，縱向范圍從-10.0um到0um的網(wǎng)格進(jìn)行了初始化的指定。參數(shù)nx=2定義了所包含三角形為2,即網(wǎng)格x方向是由2個(gè)三角形

38、構(gòu)成。共163頁(yè)83 “substrate(.)”命令命令定義硅襯底的晶向和摻雜。例如：substrate(element=b, concentration=5.0e15, orientation=100)該命令定義了硅襯底的晶向是（100），摻雜濃度為5.0*1015 atoms/cm3的硼。共163頁(yè)84 “mask(.)”命令命令在dios中，這條命令是用來(lái)對(duì)仿真中所要用到的掩膜板進(jìn)行仿真，以及完成掩膜板形成圖案的沉積。例如：mask (material=resist, thickness=800nm, x (0.1, 0.3)該命令定義了一塊厚度為800nm的光刻膠（resist表示p

39、hotoresist的意思，即光刻膠），其覆蓋的范圍是橫向位置從0.1um到0.3ummask (material=po, element=p, concentration=3e19, thickness=180nm, xleft=0.2, xright=0.4)該命令沉積了一層厚度為180nm的摻入雜質(zhì)磷的多晶硅層，其范圍為從0.2um到0.4um。共163頁(yè)85“implant(.)”命令命令這條命令是用來(lái)對(duì)離子注入進(jìn)行仿真的。其中的“function”參數(shù)允許用戶選擇使用“分析注入”還是“monte carlo注入”。如果用戶選擇前一種，則注入?yún)?shù)來(lái)自于默認(rèn)圖表。如果需要使用其它注入?yún)?shù)

40、，可以另外創(chuàng)建注入圖表，并在仿真中使用。例如：implant(element=bf2, dose=5.0e12, energy=25kev, tilt=7)該命令以傾斜角度為7，能量為25kev，注入劑量為5.0*1012 atoms/cm2的bf2離子。implant(element=as,dose=1.0e14,energy=300kev,tilt=0,rotation=-90,function=crystaltrim)該命令用monte carlo方式仿真，用crystaltrim函數(shù)注入砷離子。共163頁(yè)86“diffusion(.)”命令命令在dios中，“diffusion”是用來(lái)

41、對(duì)器件制做工藝中所有高溫步驟進(jìn)行仿真的命令。包括：熱退火、氧化、外延層的生長(zhǎng)和硅化物的生長(zhǎng)?？梢赃x擇的擴(kuò)散模型中既有簡(jiǎn)單的常量擴(kuò)散模型，也有將雜質(zhì)和點(diǎn)缺陷配對(duì)等都包括的復(fù)雜完整模型。平衡態(tài)和瞬態(tài)聚集模型允許考慮雜質(zhì)激活效應(yīng)的精確仿真。另外，還支持雜質(zhì)和點(diǎn)缺陷等參數(shù)的自定義。例如：diffusion(temperature=1050, time=10s)該命令仿真了溫度為1050度，時(shí)間為10秒的高溫環(huán)境。diffusion(temperature=1000, time=20min, atmosphere=o2)該命令仿真了干氧氧化，溫度為1000度，時(shí)間為20分鐘，氣體為o2。diffusio

42、n(atmosphere=epitaxy, time=1.0s, temperature=1050, growthrate=1000 nm /s, element=ge, concentration=1.0e20）該命令仿真了一個(gè)sige外延層的生長(zhǎng),在生長(zhǎng)外延的環(huán)境中，加入ge，濃度為1.0e20，就形成了sige的外延層，時(shí)間為1.0秒，溫度為1050度，生長(zhǎng)速率為1000 nm/s。共163頁(yè)87 “deposit(.)”命令命令在dios中，該命令是用來(lái)沉積物質(zhì)層的。用于各向同性或異性沉積、表面平整化、選擇性沉積以及化學(xué)機(jī)械拋光。例如：deposit(material=po, thic

43、kness=0.2um, element=p, conc=3.0e19)該命令進(jìn)行多晶硅層的沉積仿真，厚度為0.2um，摻雜濃度為3.0*1019 atoms/cm3的磷原子。deposit (material=ox, dtype=fill，yfill=2.0um )該命令用以仿真化學(xué)機(jī)械拋光?！癴ill”表示平整化，yfill=2.0um表示機(jī)械拋光的縱向距離。共163頁(yè)88 “ecthing(.)”命令命令該命令用來(lái)仿真刻蝕。該命令包含多個(gè)選項(xiàng)，可以在仿真中靈活的定義刻蝕形狀。例如：etching (material=ox, time=5.0min, rate(iso=100nm/min)

44、該命令仿真了一個(gè)刻蝕時(shí)間為5 分鐘，刻蝕速率為100 nm/min的各向同性的氧化物的刻蝕。共163頁(yè)89 “1d(.)”命令命令這是一個(gè)保存命令，進(jìn)行過(guò)仿真的器件，任何x-y分布的dios變量都可以通過(guò)該命令來(lái)保存。例如：1d (file=channel, xsection(0.0), species (btotal, ptotal), fac= -1.0, append=off)這是對(duì)在x= 0.0處的，硼和磷的總濃度作為深度的函數(shù)進(jìn)行保存。fac= -1.0為坐標(biāo)比例縮小因子共163頁(yè)90 “save(.)”命令命令這條命令用來(lái)保存器件的最終結(jié)構(gòu)，并且文件可以載入重新進(jìn)行仿真。在“sav

45、e”命令執(zhí)行之后，文件可以由dessis載入進(jìn)行器件仿真。例如：save(file=tst)把器件保存為文件“tst.dmp.gz”。save（file=nmos, type=mdraw）保存為mdraw格式，提供dessis作為器件仿真文件共163頁(yè)91dessisnise-tcad的仿真結(jié)構(gòu)流程共163頁(yè)92file * 輸入文件：grid = nmos_mdr.grddoping = nmos_mdr.dat* 輸出文件plot = n3_des.datcurrent = n3_des.pltoutput = n3_des.log 共163頁(yè)931.“file”部分主要定義器件結(jié)構(gòu)的輸入

46、文件和輸出文件的名稱；2. “ * ”引導(dǎo)注釋行；3.“grid”和“doping”語(yǔ)句分別指定器件結(jié)構(gòu)的網(wǎng)格文件和摻雜文件；4.“plot”語(yǔ)句定義仿真時(shí)計(jì)算的變量，擴(kuò)展名為“_des.dat”；5.“current”語(yǔ)句定義最后輸出的電學(xué)數(shù)據(jù)（比如電流、電壓、電極上電荷），擴(kuò)展名為“_des.plt”；6.“output”語(yǔ)句定義輸出日志文件，記錄dessis運(yùn)行情況，擴(kuò)展名為“_des.log”。共163頁(yè)94electrode name=source voltage=0.0 name=drain voltage=0.1 name=gate voltage=0.0 barrier=-0.

47、55 name=substrate voltage=0.0 共163頁(yè)951.“electrode”部分定義器件的電極相關(guān)信息。2. 值得注意的是，在多晶硅“gate”上，接觸定義必須是歐姆接觸。3.“name=”語(yǔ)句定義每個(gè)電極，這個(gè)電極名稱必須和grid文件定義一致；4.“voltage=0.0”語(yǔ)句定義電極的電壓初始值；5.“barrier=-0.55”語(yǔ)句定義金屬半導(dǎo)體功函數(shù)差，這樣多晶硅電極才能把它當(dāng)成金屬。共163頁(yè)96physics mobility (dopingdep highfieldsat enormal)effectiveintrinsicdensity (bandga

48、pnarrowing (oldslotboom)共163頁(yè)971.“physics”部分定義器件仿真過(guò)程中使用的物理模型。2.“mobility (dopingdep highfieldsat enormal)”語(yǔ)句定義三個(gè)模型：摻雜依賴（doping dependence）模型、高電場(chǎng)飽和模型、橫向電場(chǎng)依賴（transverse field dependence）模型；3.“effectiveintrinsicdensity (bandgapnarrowing (oldslotboom)”語(yǔ)句定義硅能隙窄化模型，它決定載流子的濃度。共163頁(yè)98plot edensity hdensity

49、ecurrent hcurrentpotential spacecharge electricfieldemobility hmobility evelocity hvelocitydoping donorconcentration acceptorconcentration1.plot”部分定義所有的計(jì)算變量，dessis要仿真的變量都將被存入plot文件。共163頁(yè)99math extrapolaterelerrcontrol1.“math”部分定義dessis仿真時(shí)算法的設(shè)置，包括仿真器類型、仿真誤差標(biāo)準(zhǔn)的設(shè)置。2.“extrapolate”語(yǔ)句定義仿真時(shí)采用外推法定義迭代下一步的數(shù)值；

50、3.“relerrcontrol”語(yǔ)句定義迭代反復(fù)計(jì)算時(shí)加入誤差控制。共163頁(yè)100solve #初始解決方案：poissoncoupled poisson electron quasistationary (maxstep=0.05goal name=gate voltage=2 ) coupled poisson electron 共163頁(yè)1011. “solve”部分定義一系列的仿真，包括仿真所需要的一些參數(shù)。2. “poisson”語(yǔ)句定義初始化采用非線性泊松方程；3. “coupled poisson electron ”語(yǔ)句定義在初始偏置下電子的連續(xù)性方程；4. 這條語(yǔ)句定義仿

51、真的一些設(shè)定，包括最大步長(zhǎng)0.05，柵壓仿真到2v，采用泊松方程仿真。共163頁(yè)102nmos的輸出特性共163頁(yè)103互動(dòng)時(shí)間 any question?共163頁(yè)104休息時(shí)間共163頁(yè)105單元2 本單元講述了幾個(gè)用tsuprem4/medici仿真esd的幾個(gè)例子：共163頁(yè)106單元2 2.1：直流仿真 2.2：混合電路仿真 2.3：溫度仿真 2.4：極值功率密度 2.5：功率分布仿真共163頁(yè)1072.1：直流仿真n直流仿真ggnmos結(jié)構(gòu)圖共163頁(yè)108n直流仿真ggnmos的i-v圖共163頁(yè)109n直流仿真ggnmos結(jié)構(gòu)圖共163頁(yè)110n直流仿真scr的i-v圖共163頁(yè)1112.2：混合電路仿真nhbm放電模式的等效電路圖共163頁(yè)112n混合電路仿真的器件共163頁(yè)113n5kv的esd情況下的i-t，v-t圖。共163頁(yè)114n5kv的esd情況下的i-t，v