海南4+1

扫描电子显微镜工作原理及主要结构(一)
来源/作者:中国标准物质网  日期:2017-12-21

SAOMIAODIANZIXIANWEIJING(JIANCHENGSAOMIAODIANJING)SHIYIZHONGDAXINGJINGMIYIQI,TASHIJIXIEXUE、GUANGXUE、DIANZIXUE、REXUE、CAILIAOXUE、ZHENKONGJISHUDENGDUOMENXUEKEDEZONGHEYINGYONG。

1.GONGZUOYUANLI

SAOMIAODIANJINGYOUDIANZIQIANGFASHECHUDIANZISHU(ZHIJINGYUE50um),ZAIJIASUDIANYADEZUOYONGXIAJINGGUOCITOUJINGXITONGHUIJU,XINGCHENGZHIJINGWEI5 nmDEDIANZISHU,JUJIAOZAIYANGPINBIAOMIANSHANG,ZAIDIERJUGUANGJINGHEWUJINGZHIJIANPIANZHUANXIANQUANDEZUOYONGXIA,DIANZISHUZAIYANGPINSHANGZUOGUANGZHAZHUANGSAOMIAO,DIANZIHEYANGPINXIANGHUZUOYONGCHANSHENGXINHAODIANZI。ZHEIXIEXINHAODIANZIJINGTANCEQISHOUJIBINGZHUANHUANWEIGUANGZI,ZAIJINGGUODIANXINHAOFANGDAQIJIAYIFANGDACHULI,ZUIZHONGCHENGXIANGZAIXIANSHIXITONGSHANG。

SHIYANGKEWEIKUAIZHUANGHUOFENMOKELI,CHENGXIANGXINHAOKEYISHIERCIDIANZI、BEISANSHEDIANZIHUOXISHOUDIANZI。QIZHONGERCIDIANZISHIZUIZHUYAODECHENGXIANGXINHAO。YOUDIANZIQIANGFASHEDENENGLIANGWEI5~35keVDEDIANZI,YIQIJIAOCHABANZUOWEIDIANZIYUAN,JINGERJIJUGUANGJINGJIWUJINGDESUOXIAOXINGCHENGJUYOUYIDINGNENGLIANG、YIDINGSHULIUQIANGDUHESHUBANZHIJINGDEWEIXIDIANZISHU,ZAISAOMIAOXIANQUANQUDONGXIA,YUSHIYANGBIAOMIANANYIDINGSHIJIAN、KONGJIANSHUNXUZUOZHAWANGSHISAOMIAO。JUJIAODIANZISHUYUSHIYANGXIANGHUZUOYONG,CHANSHENGERCIDIANZIFASHE(YIJIQITAWULIXINHAO),ERCIDIANZIFASHELIANGSUISHIYANGBIAOMIANXINGMAOERBIANHUA。ERCIDIANZIXINHAOBEITANCEQISHOUJIZHUANHUANCHENGDIANXINHAO,JINGSHIPINFANGDAHOUSHURUDAOXIANXIANGGUANZHAJI,DIAOZHIYURUSHEDIANZISHUTONGBUSAOMIAODEXIANXIANGGUANLIANGDU,KEDEDAOFANYINGSHIYANGBIAOMIANXINGMAODEERCIDIANZIXIANG。

2.ZHUYAOJIEGOU

SAOMIAODIANZIXIANWEIJINGDEJIEGOUBAOKUODIANZIGUANGXUEXITONG、XINHAOSHOUJI、TUXIANGXIANSHIHEJILUXITONG、ZHENKONGXITONG。TU24-1、TU24-2WEISAOMIAODIANZIXIANWEIJINGWAIXINGTUHEZHUJIGOUZAOSHIYITU。

2.1DIANZIGUANGXUEXITONG

这部分主要由电子枪、电磁透镜、扫描线圈、样品室组成。电子枪提供一个稳定的电子源,形成电子束,一般使用钨丝阴极电子枪,用直径约为0.1 mm的钨丝,弯成发夹形,形成半径约为100um的V形尖端。当灯丝电流通过时,灯丝被加热,达到工作温度后便发射电子,在阴极和阳极间加有高压,这些电子则向阳极加速运动,形成电子束。电子束在高压电场作用下,被加速通过阳极轴心孔进入电磁

TU24-1     JEOLJSM-6380LVXINGSAOMIAODIANZIXIANWEIJINGWAIXINGTU

TOUJINGXITONG。GAIXITONGYOUJUGUANGJINGHEWUJINGZUCHENG,QIZUOYONGSHIYIKAOTOUJINGDEDIANCICHANGYUYUNDONGDIANZIXIANGHUZUOYONGSHIDIANZISHUJUJIAO,JIANGDIANZIQIANGFASHEDEDIANZISHU10~50umYASUOCHENG5~20nm,SUOXIAODAOYUE1/10000。JUGUANGJINGKEYIGAIBIANRUSHEDAOYANGPINSHANGDIANZISHULIUDEDAXIAO,WUJINGJUEDINGDIANZISHUSHUBANDEZHIJING。DIANZIGUANGXUEXITONGZHONGCUNZAIDEQIUCHA、SECHA、XIANGSANDENG,DOUHUIYINGXIANGZUIZHONGTUXIANGDEZHILIANG。QIUCHADECHANSHENGSHIYUANLIGUANGZHOUGUIJISHANGYUNDONGDEDIANZIBIJINZHOUDIANZISHOUDAODEJUJIAOZUOYONGGENGQIANG。KEFUDEFANGFASHIZAIDIANZIGUANGXUEDEGUANGZHOUZHONGJIASANJIGUDINGGUANGLANDANGZHUFASANDEDIANZISHU,GUANGLANTONGCHANGCAIYONGHOUDUWEI0.05mmDEMUPIANZHIZUO,WUJINGXIAOXIANGSANQITIGONGYIGEYUWUJINGBUJUNYUNCICHANGXIANGFANDEXIAOZHENGCICHANG,SHIWUJINGZUIZHONGXINGCHENGYIGEDUICHENGCICHANG,CHANSHENGYISHUXIJUJIAODEDIANZISHU。

SAOMIAOXITONGZHUYAOBAOKUOSAOMIAOFASHENGQI、SAOMIAOXIANQUANHEFANGDABEILVBIANHUANQI,SAOMIAOFASHENGQIYOUXSAOMIAOFASHENGQIHEYSAOMIAOFASHENGQIZUCHENG,CHANSHENGDEBUTONGPINLVDEJUCHIBOXINHAOBEITONGBUSONGRUJINGTONGZHONGDESAOMIAOXIANQUANHEXIANSHIXITONGCRTZHONGDESAOMIAOXIANQUANSHANG。JINGTONGDESAOMIAOXIANQUANFENSHANG、XIASHUANGPIANZHUANSAOMIAOZHUANGZHI,QIZUOYONGSHISHIDIANZISHUZHENGHAOLUOZAIWUJINGGUANGLANKONGZHONGXIN,BINGZAIYANGPINSHANGJINXINGGUANGZHASAOMIAO。

扫描方式分点扫描、线扫描、面扫描和Y调制扫描。扫描电镜图像的放大倍率是通过改变电子束偏转角度来调节的。放大倍数等于CRT面积与电子束在样品上扫描的面积之比,减小样品上扫描的面积,就可增加放大倍率。不同放大倍率在样品上扫描的面积见表24-1。

TU24-2     SAOMIAODIANZIXIANWEIJINGZHUJIJIEGOUSHIYI

表24-1     不同放大倍率在样品上扫描的面积

DIANZISHUZAIYANGPINSHANGSAOMIAODEMIANJI,YOUSAOMIAOXIANQUANCHANSHENGDEJILICICHANGKONGZHI,KEYILIANXUDIAOJIE,SUOYISAOMIAODIANJINGDEFANGDABEILVSHIKEYILIANXUDIAOJIEDE。

样品室内除放置样品外,还安置信号探测器。不同信号的收集和相应探测器的安放位置有很大的关系,如果安置不当,则有可能收不到信号或收到的信号很弱,从而影响分析精度。样品台本身是一个复杂而精密的组件,它应能夹持一定尺寸的样品,并能使样品平移、倾斜和转动,以利于对样品上每一特定位置进行各种分析。新式扫描电子显微镜的样品室实际上是一个微型试验室,它带有多种附件,可使样品在样品台上加热、冷却和进行机械性能试验(如拉伸和疲劳)。

【关键词】中国标准物质