1/74半导体器件原理主讲人:蒋玉龙本部微电子学楼312室,65643768Email:yljiang@fudan.edu.cnhttp://10.14.3.1212/74第四章小尺寸MOSFET的特性4.1MOSFET的短沟道效应和窄沟道效应4.2小尺寸MOSFET的直流特性4.3MOSFET的按比例缩小规律3/744.1MOSFET的短沟道效应和窄沟道效应14.1.1MOSFET的短沟道效应(SCE)1.阈值电压“卷曲”(VTroll-off)2.漏感应势垒降低(DIBL)3.速度饱和效应4.亚阈特性退化5.热载流子效应4/744.1MOSFET的短沟道效应和窄沟道效应24.1.2阈值电压“卷曲”(VTroll-off)1.现象短沟道效应窄沟道效应5/744.1MOSFET的短沟道效应和窄沟道效应34.1.2阈值电压“卷曲”(VTroll-off)2.原因长沟道MOSFET短沟道MOSFETsyxxyx),(),(22syxyyxxyx),(),(),(2222GCA:0),(22yyxp-Sip-Si0),(22yyx6/744.1MOSFET的短沟道效应和窄沟道效应44.1.2阈值电压“卷曲”(VTroll-off)2.原因2222),(),(),(yyxyxxyxsseffyx),(p-SiAeffANNVT3.电荷分享模型(Poon-Yau)oxBBFBTCQVVV2BSBBFBVVVV22NMOSoxBBFBTCQVVV''2BSBBBBFBVVQQVV22'7/744.1MOSFET的短沟道效应和窄沟道效应44.1.2阈值电压“卷曲”(VTroll-off)3.电荷分享模型(Poon-Yau)计算QB’/QB(电荷分享因子F)LLLdLdQQBB1221maxmax'jjxddx2/12max2maxjxdrL2/12max221212/1maxjjxdx12112/1max'jjBBxdLxQQ1211222/1max'jjBSBBFBTxdLxVVVVVVDS=0NMOS8/744.1MOSFET的短沟道效应和窄沟道效应54.1.2阈值电压“卷曲”(VTroll-off)3.电荷分享模型(Poon-Yau)讨论QB’/QB(电荷分享因子F)dmax/xj较小时dmax/xj较大时LdQQFBBmax'1LdxdLxQQFjjBBmax2/1max'11211经验参数(>1)12122/1max'jjBSBTTTxdLxVVVVVBSBoxoxsVVLt22BSBVVLd2max1oLFVT2otoxVT3oNAdmaxFVT4oxjVT9/744.1MOSFET的短沟道效应和窄沟道效应64.1.2阈值电压“卷曲”(VTroll-off)3.电荷分享模型(Poon-Yau)讨论QB’/QB(电荷分享因子F)当VDS>0时oxBSBAsDSTLCVVNqyyV5.0211'DSBByyLQQFVDSFVT抑制VTroll-off的措施:1oxj2oNA3otox4oVBS5oVDS10/744.1MOSFET的短沟道效应和窄沟道效应74.1.3反常短沟道效应(RSCE/VTroll-up)1.现象11/744.1MOSFET的短沟道效应和窄沟道效应84.1.3反常短沟道效应(RSCE/VTroll-up)2.原因MOS“重新氧化”(RE-OX)工艺OED:氧化增强扩散12/744.1MOSFET的短沟道效应和窄沟道效应94.1.3反常短沟道效应(RSCE/VTroll-up)3.分析00exp)(GyQyQfsfs单位:[C/cm2]横向分布的特征长度源(漏)端杂质电荷面密度单位:[C]0002exp12GLLCGQoxfsLWCQVoxFST0002/02exp12)(2GLWGQdyyQWQfsLfsFS13/744.1MOSFET的短沟道效应和窄沟道效应104.1.4窄沟道效应(NEW)1.现象WVT短沟道效应窄沟道效应14/744.1MOSFET的短沟道效应和窄沟道效应114.1.4窄沟道效应(NEW)2.边缘耗尽效应BSBBFBTVVVVV22,宽沟oxBCQoxWBSBBFBTCQVVVVV22,窄沟WddWdQQBWmaxmax2max221WQBQWSiO2dmaxxzy¼圆弧:一般地,引入经验参数GWWdGQQWBWmax15/744.1MOSFET的短沟道效应和窄沟道效应124.1.4窄沟道效应(NEW)3.三种氧化物隔离结构的NWERaisedfield-oxideisolation:WVTLOCOS:WVTSTI:WVT反窄沟道效应(inverseNWE)16/744.1MOSFET的短沟道效应和窄沟道效应134.1.4窄沟道效应(NEW)4.杂质横向扩散的影响杂质浓度边缘高,中间低边缘不易开启随着WVT窄沟道效应17/744.1MOSFET的短沟道效应和窄沟道效应144.1.5漏感应势垒降...