半導(dǎo)體物理 第七章 金屬和半導(dǎo)體的接觸1

1、重點(diǎn) 1、阻擋層與反阻擋層的形成 2、肖特基勢壘的定量特性 3、歐姆接觸的特性 第七章 金屬和半導(dǎo)體的接觸Contact between Metal and Semiconductor7.1 金屬-半導(dǎo)體接觸和能帶圖Contact between Metal and Semiconductor and Band Diagram重點(diǎn) 功函數(shù) 電子親和勢 接觸電勢勢壘 阻擋層與反阻擋層 1、功函數(shù)Wm 、Ws與電子親和勢 EcEvWmWsEFmEFsE0EnContact between Metal and Semiconductor and Band DiagramWsEnE0EcEFsCont

2、act between Metal and Semiconductor and Band DiagramEvEFm2、接觸電勢差 Contact between Metal and Semiconductor and Band Diagram 接觸勢壘： Wm-Ws= -q（Vms+Vs）- qVmsContact between Metal and Semiconductor and Band Diagram導(dǎo)帶底電子向金屬運(yùn)動(dòng)時(shí)必須越過的勢壘的高度： qVD=Wm-Ws （1）金屬一邊的電子運(yùn)動(dòng)到半導(dǎo)體一邊也需要越過的勢壘高度：qVDEcEFEvContact between Metal

3、and Semiconductor and Band Diagram3、阻擋層與反阻擋層 Contact between Metal and Semiconductor and Band Diagram（1）金屬-n型半導(dǎo)體接觸Contact between Metal and Semiconductor and Band Diagram（a） WmWs 電子阻擋層: Contact between Metal and Semiconductor and Band DiagramContact between Metal and Semiconductor and Band Diagram金屬

4、一邊的勢壘 半導(dǎo)體一邊的勢壘 Contact between Metal and Semiconductor and Band Diagram（b） WmWm 空穴阻擋層: EFmEFsWsWmEvEcE0Contact between Metal and Semiconductor and Band DiagramqVD=Ws-Wm xDEFEvEcContact between Metal and Semiconductor and Band Diagram（2）WmWs 空穴反阻擋層:WsWmEFsEFmEvEcE0Contact between Metal and Semiconduc

5、tor and Band Diagram接觸后：EFEcEvxDContact between Metal and Semiconductor and Band Diagram3、表面態(tài)對(duì)接觸勢壘的影響表 面 態(tài)：局域在表面附近的新電 子態(tài)。 表面能級(jí)：與表面態(tài)相應(yīng)的能 級(jí)稱為表面能級(jí)。Contact between Metal and Semiconductor and Band DiagramA、接觸前，半導(dǎo)體體內(nèi)與表面電 子態(tài)未交換電子 E0EFmWmWsWlEvEFS0EF0表面能級(jí)Contact between Metal and Semiconductor and Band DiagramB、接觸前，半導(dǎo)體體內(nèi)與表面電子態(tài)交換電子后 能帶彎曲量 qVD=EF0-EFs0 與金屬的性能無關(guān) 半導(dǎo)體的功函數(shù)則變?yōu)椋?EFmWlqVDEnqVDEFsWmWlE0EvEFEcContact between Metal and Semiconductor and Band DiagramC、金屬與半導(dǎo)體接觸后qVD Ec（0） EcEvContact between Metal and Semiconductor and Ban