MOS器件的热载流子效应

Hot Carriers Effect of MOS Devices

热载流子效应产生的原因，首先是在沟道强电场中形成迁移率偏低的热载流子，然后由于碰撞电离而使热载流子大量增加。热电子和热空穴能够越过界面势垒向栅氧化层发射。进入栅氧化层的热载流子，或者穿透氧化层，或者造成随时间而增加的界面态，或者造成载流子陷阱。热电子或热空穴也可以受结电场的作用而进入衬底。抑制热载流子效应的方向，一是在沟道两侧制作轻掺杂区，以降低沟道电场强度；二是对栅氧化层进行氮化处理和提高氧化温度，以改善氧化层的质量，增强抗热载流子效应的能力。

The cause of hot carriers effect genration is that channel high electric fieldgenerates hot carriers of lower mobility,then these generated hot carriers generate more hotcarriers bv impact ionization crystal atoms at the drain end of the channel.Hot electronsand hot holes can cross interface barrier into gate oxide,and these hot carriers either pene-trate gate oxidic layer or generate interface states as well as carrier traps. Besides,hot elec-trons and hot holes may be driven to substrate by electric field force at the drain end.THemeasures of restraining hot carriers effect include:(a).Constructing a lightly doped regionat the both ends of the channel in order to reduce the channel field.(b).Nitriding gateoxidic lager and increasing oxidic temperature so as to improve the quality of gate oxidiclayer and enhance the resisting of hot carriers effect.