Reduction of the threshold voltage dispersion in nanometer-sized arrays showing Coulomb blockade

Until now, the tunnel multijunctions (based on arrays of nanometer-size metallic dots on a SiO2 substrate) are the only devices that are able to control single electrons while remaining compatible with the silicon technology. There are, however, two serious drawbacks. First, the position and size of the dots are not accurately controllable, and therefore the arrays are necessarily highly disordered. Secondly, only 2D arrays can be produced with a high yield. This leads to a large dispersion of the critical electrical parameters, especially the threshold voltage Vth in the useful high temperature range. For any large scale integration application, the dispersion should definitely be much smaller than 10%. By a numerical simulation of random sets of devices, we will show there that the design proposal previously made by us allows a drastic reduction of the Vth dispersion in these highly disordered arrays.