SOI和体硅MOSFET大信号非准静态效应比较研究

Comparison of Large-Signal Non-Quasi-Static Effect of SOI and Bulk MOSFET's

研究了全耗尽SOI、部分耗尽SOI和体硅NMOS器件中源、漏、栅和衬底电流的非准静态现象。研究表明,在相同的结构参数下,体硅器件的非准静态效应最强,PDSOI次之,FDSOI最弱。指出了沟道源、漏端反型时间和反型程度的不同是造成非准静态效应的内在原因。最后提出临界升压时间的概念,以此对非准静态效应进行定量表征,深入研究器件结构参数对非准静态效应的影响规律。结果显示,通过缩短沟道长度、降低沟道掺杂浓度、减小硅膜厚度和栅氧厚度、提高埋氧层厚度等手段,可以弱化SOI射频MOS器件中的非准静态效应。

NQS effects of source,drain,gate and body currents in FDSOI,PDSOI and bulk NMOS were investigated.It has been shown that,for the same structure parameters,bulk device had the strongest NQS effect,and next to it was PDSOI device,while FDSOI device had the weakest NQS effect.Differences in inversion time and magnitude of the channel near source and drain were origins of NQS effect.Furthermore,a critical ramp time was proposed to quantitatively characterize NQS effect.Influences of geometric parameters on NQS effects were studied in detail.Results showed that NQS effect in RF SOI MOSFET could be depressed by shrinking channel length,decreasing impurity concentration,reducing thicknesses of silicon film and gate oxide,and increasing thickness of buried oxide.