Characteristic Variations Induced by Random Fluctuation of Source/Drain Lateral Distribution Dopant in Nano-Scale UTB SOI MOSFET

• Main Authors: Du, Linfeng, Deng, Hui, Du, Gang, Han, Ruqi, Zhang, Shengdong
• Format: Conference Proceeding
• Language: English
• ISSN: 1938-5862; 1938-6737
• DOI: 10.1149/1.3096431

The "nominally" un-doped or lightly-doped channels are actually doped considerably due to the lateral distribution of dopants from Source/Drain (S/D) doping, thus forming a new source of Random Dopant Fluctuation (RDF). In this work, the unexpected RDF effect of sub-20nm UTB SOI MOSFETs is investigated by device simulation. A new method to simulate the RDF effect was introduced. The results show that a severe Vth variation due to the new RDF effect will take place when device is scaled into sub-20 nm regime, even with un-doped channel. The device parameter dependence of Vth variations of MOSFETs with un-doped channel were presented, which was found to be largely similar to that of ones with doped channel. The drain current and subthreshold fluctuations were also investigated to gain a more comprehensive insight to RDF in MOSFETs. Our results illustrated the importance of suppressing the lateral distribution of S/D dopants for scaled devices.