INFLUENCE OF ENERGY AND DOSE OF IMPLANTED IONS ON THRESHOLD VOLTAGE OF MOS STRUCTURE.

ANIL KUMAR; G. S. VIRDI

Volume : VIII, Issue : IV, April - 2019

INFLUENCE OF ENERGY AND DOSE OF IMPLANTED IONS ON THRESHOLD VOLTAGE OF MOS STRUCTURE.

Anil Kumar, G. S. Virdi

Abstract :

This work carried out with a view to study the variation of threshold voltage of MOS structure grown on non–uniformly doped substrate. The authors have used ion– implantation as a method of growing non–homogeneously doped layer on silicon substrate .Boron implantation in p–type substrate with different doses of Boron ions, varying from 1x1012 ions/cm2 to 1x1015 ions/cm2 and energies 20Kev to 120Kev is considered ,which provides a variety of impurity profiles in the substrate. Capacitance–Voltage curves have been obtained from the numerical solution of Poisson’s equation. The threshold voltage has been assumed to be given by voltage applied to the gate of MOS structure at which strong inversion take place. This has been observed that as the energy of the implanted ions is increased ,keeping the dose fixed at 1x1014ions /cm2,the threshold voltage of MOS capacitor faicated on this substrate decreases . where as when the dose of the Boron implanted ions is increased ,keeping the energy fixed at 50Kev ,the threshold voltage increases .Thus the threshold voltage of MOS capacitor not only be controlled by the Dose of the implanted ions in the substrate but also by the energy of the implanted ions, because both these parameters ing about changes in impurity concentration profiles in the substrate.