Detection of individual dopants in singe-electron devices - a study by KFM observation and simulation

Single electron devices (SEDs) are candidates to become a keystone of future electronics. They are very attractive due to low power consumption, small size or high operating speed. It is even possible to assure compatibility with present CMOS technology when natural potential fluctuations introduced by dopant atoms are used to create quantum dots (QD). However, the main problem of this approach is due to the randomness of dopant distribution which is characteristic for conventional doping techniques. This leads to scattered characteristics of the devices, which precludes from using them in the circuits. In these work we approach the problem of correlating the distribution of QD's with the device characteristics. For that, we investigate with a Kelvin probe force microscope (KFM) the surface potential of Si nanodevice channel in order to understand the potential landscape. Results reveal the features ascribable to individual dopants. These findings are supported also by simulation results.