mos击穿,mos管(guan)击穿的原因及解决方(fang)法-分析大全
信息来源:本站 日期:2017-10-27
(1)穿(chuan)(chuan)通(tong)击穿(chuan)(chuan)的(de)击穿(chuan)(chuan)点(dian)软(ruan),击穿(chuan)(chuan)过程中,电流有逐渐(jian)增(zeng)大(da)(da)的(de)特征,这是因为耗尽(jin)层扩展较宽,发生电流较大(da)(da)。另一(yi)方面,耗尽(jin)层展广大(da)(da)容易发生DIBL效(xiao)应,使(shi)源衬底结正偏呈(cheng)现电流逐渐(jian)增(zeng)大(da)(da)的(de)特征。
(2)穿(chuan)通(tong)击(ji)穿(chuan)的(de)软(ruan)击(ji)穿(chuan)点(dian)发生(sheng)在源漏的(de)耗(hao)(hao)(hao)尽层(ceng)相接(jie)时(shi)(shi),此刻源端的(de)载流(liu)(liu)(liu)子(zi)注(zhu)入到耗(hao)(hao)(hao)尽层(ceng)中(zhong), 被耗(hao)(hao)(hao)尽层(ceng)中(zhong)的(de)电(dian)场(chang)加(jia)快到达漏端,因此,穿(chuan)通(tong)击(ji)穿(chuan)的(de)电(dian)流(liu)(liu)(liu)也有(you)急(ji)剧增(zeng)(zeng)大(da)(da)点(dian),这(zhei)(zhei)个电(dian)流(liu)(liu)(liu)的(de)急(ji)剧增(zeng)(zeng)大(da)(da)和雪崩(beng)击(ji)穿(chuan)时(shi)(shi)电(dian)流(liu)(liu)(liu)急(ji)剧增(zeng)(zeng)大(da)(da)不同,这(zhei)(zhei)时(shi)(shi)的(de)电(dian)流(liu)(liu)(liu)相当于源衬(chen)底PN结(jie)正向(xiang)导通(tong)时(shi)(shi)的(de)电(dian)流(liu)(liu)(liu),而雪崩(beng)击(ji)穿(chuan)时(shi)(shi)的(de)电(dian)流(liu)(liu)(liu)主要(yao)为PN结(jie)反向(xiang)击(ji)穿(chuan)时(shi)(shi)的(de)雪崩(beng)电(dian)流(liu)(liu)(liu),如不作(zuo)限流(liu)(liu)(liu),雪崩(beng)击(ji)穿(chuan)的(de)电(dian)流(liu)(liu)(liu)要(yao)大(da)(da)。
(3)穿(chuan)通(tong)击(ji)(ji)穿(chuan)一般不会呈现(xian)破(po)坏性击(ji)(ji)穿(chuan)。因为穿(chuan)通(tong)击(ji)(ji)穿(chuan)场(chang)强没有到(dao)达(da)雪崩击(ji)(ji)穿(chuan)的场(chang)强,不会发生(sheng)许多电子空(kong)穴对。
(4)穿(chuan)通(tong)击穿(chuan)一般(ban)发生在沟道(dao)体内,沟道(dao)外表不容易发生穿(chuan)通(tong),这主(zhu)要是(shi)因(yin)为沟道(dao)注入使外表浓(nong)度(du)比浓(nong)度(du)大构(gou)成,所以,对NMOS管一般(ban)都有防穿(chuan)通(tong)注入。
(5)一般的,鸟嘴(zui)边际的浓度比沟(gou)道中(zhong)心(xin)浓度大,所以穿通击穿一般发生(sheng)在沟(gou)道中(zhong)心(xin)。
(6)多晶栅长(zhang)度对穿(chuan)(chuan)通击穿(chuan)(chuan)是(shi)有(you)影响的,跟着栅长(zhang)度添加,击穿(chuan)(chuan)增大。而对雪崩击穿(chuan)(chuan),严格(ge)来说也(ye)有(you)影响,可是(shi)没有(you)那么明显。
第一(yi)、MOS管本身(shen)的输入电(dian)(dian)(dian)(dian)阻很高(gao)(gao),而(er)栅-源极间(jian)电(dian)(dian)(dian)(dian)容又十分(fen)小,所以极易(yi)受外界电(dian)(dian)(dian)(dian)磁场或静电(dian)(dian)(dian)(dian)的感应而(er)带电(dian)(dian)(dian)(dian),而(er)少(shao)数电(dian)(dian)(dian)(dian)荷就可在(zai)极间(jian)电(dian)(dian)(dian)(dian)容上构成(cheng)相当高(gao)(gao)的电(dian)(dian)(dian)(dian)压(ya)(ya)(U=Q/C),将管子损坏。尽管MOS输入端有(you)抗静电(dian)(dian)(dian)(dian)的维护措施,但仍需当心对(dui)待,在(zai)存储和运送中(zhong)最好用(yong)金属容器(qi)或许导电(dian)(dian)(dian)(dian)资(zi)料包装(zhuang),不要(yao)放(fang)在(zai)易(yi)发生静电(dian)(dian)(dian)(dian)高(gao)(gao)压(ya)(ya)的化(hua)工(gong)资(zi)料或化(hua)纤织物中(zhong)。拼装(zhuang)、调试时,东西、外表、工(gong)作(zuo)台(tai)等均应杰(jie)出接(jie)(jie)地(di)。要(yao)避免(mian)操作(zuo)人(ren)员(yuan)的静电(dian)(dian)(dian)(dian)搅扰构成(cheng)的损坏,如不宜(yi)穿尼龙、化(hua)纤衣服(fu),手或东西在(zai)触摸集(ji)成(cheng)块(kuai)前最好先接(jie)(jie)一(yi)下地(di)。对(dui)器(qi)材引线矫(jiao)直曲折或人(ren)工(gong)焊接(jie)(jie)时,运用(yong)的设(she)备有(you)必要(yao)杰(jie)出接(jie)(jie)地(di)。
第二、MOS电(dian)(dian)路输(shu)入(ru)端的(de)维护(hu)(hu)二极管(guan),其(qi)导通(tong)时(shi)(shi)电(dian)(dian)流(liu)容限(xian)一(yi)(yi)般为(wei)1mA 在可(ke)能呈现过(guo)大瞬态输(shu)入(ru)电(dian)(dian)流(liu)(超越10mA)时(shi)(shi),应串接输(shu)入(ru)维护(hu)(hu)电(dian)(dian)阻(zu)。而129#在初期设计时(shi)(shi)没有(you)参加维护(hu)(hu)电(dian)(dian)阻(zu),所(suo)以(yi)这也(ye)是MOS管(guan)可(ke)能击(ji)穿(chuan)的(de)原因,而经过(guo)替换一(yi)(yi)个内部有(you)维护(hu)(hu)电(dian)(dian)阻(zu)的(de)MOS管(guan)应可(ke)避免(mian)此(ci)种失效的(de)发生。还有(you)因为(wei)维护(hu)(hu)电(dian)(dian)路吸收的(de)瞬间能量有(you)限(xian),太大的(de)瞬间信号和(he)过(guo)高的(de)静电(dian)(dian)电(dian)(dian)压将使(shi)维护(hu)(hu)电(dian)(dian)路失去效果。所(suo)以(yi)焊(han)接时(shi)(shi)电(dian)(dian)烙铁(tie)(tie)有(you)必(bi)要可(ke)靠(kao)接地,以(yi)防漏电(dian)(dian)击(ji)穿(chuan)器(qi)材输(shu)入(ru)端,一(yi)(yi)般运用时(shi)(shi),可(ke)断电(dian)(dian)后使(shi)用电(dian)(dian)烙铁(tie)(tie)的(de)余热进行焊(han)接,并先焊(han)其(qi)接地管(guan)脚。
MOS是(shi)电(dian)(dian)压驱动元件,对(dui)(dui)电(dian)(dian)压很敏感,悬空的(de)G很容易接(jie)受外部搅扰(rao)使(shi)MOS导通,外部搅扰(rao)信号(hao)对(dui)(dui)G-S结电(dian)(dian)容充电(dian)(dian),这个(ge)细小的(de)电(dian)(dian)荷(he)能(neng)够(gou)贮存很长时(shi)刻。在实验中G悬空很风险,许多就因为这样(yang)爆管,G接(jie)个(ge)下拉电(dian)(dian)阻对(dui)(dui)地,旁路搅扰(rao)信号(hao)就不会直通了,一般能(neng)够(gou)10~20K。
这个(ge)电阻称为栅(zha)极电阻。效果1:为场效(xiao)应(ying)管供给(ji)偏(pian)置(zhi)电压;效果2:起到(dao)泻放电(dian)阻(zu)的(de)(de)效(xiao)(xiao)(xiao)果(guo)(维护栅(zha)极(ji)(ji)G~源(yuan)极(ji)(ji)S)。榜首个效(xiao)(xiao)(xiao)果(guo)好了解(jie),这儿解(jie)释一下第(di)二个效(xiao)(xiao)(xiao)果(guo)的(de)(de)原理:维护栅(zha)极(ji)(ji)G~源(yuan)极(ji)(ji)S:场(chang)(chang)效(xiao)(xiao)(xiao)应(ying)管的(de)(de)G-S极(ji)(ji)间(jian)的(de)(de)电(dian)阻(zu)值是很(hen)大的(de)(de),这样只要有(you)少数的(de)(de)静(jing)电(dian)就能(neng)使他(ta)的(de)(de)G-S极(ji)(ji)间(jian)的(de)(de)等效(xiao)(xiao)(xiao)电(dian)容两头发生(sheng)很(hen)高(gao)的(de)(de)电(dian)压,如果(guo)不及时把(ba)这些少数的(de)(de)静(jing)电(dian)泻放掉,他(ta)两头的(de)(de)高(gao)压就有(you)可(ke)能(neng)使场(chang)(chang)效(xiao)(xiao)(xiao)应(ying)管发生(sheng)误动作,甚(shen)至有(you)可(ke)能(neng)击穿其G-S极(ji)(ji);这时栅(zha)极(ji)(ji)与源(yuan)极(ji)(ji)之间(jian)加(jia)的(de)(de)电(dian)阻(zu)就能(neng)把(ba)上述的(de)(de)静(jing)电(dian)泻放掉,然(ran)后(hou)起到(dao)了维护场(chang)(chang)效(xiao)(xiao)(xiao)应(ying)管的(de)(de)效(xiao)(xiao)(xiao)果(guo)。