Electrical Characteristics of CoSi2 Layers Formed by Mevva Implantation of Co into Si

Abstract

AbstractHigh dose Co implantation into Si has been performed with a metal vapor vacuum arc (MEVVA) ion source at an extraction voltage of 70 kV to doses from 8×1016 to 6×1017 ions cm−2 at substrate temperatures (Ts) in the range of 210°C to 700°C. Annealing was performed in nitrogen at various temperatures for various time intervals by either furnace annealing (FA) or rapid thermal annealing (RTA). The electrical properties of the CoSi2 layers formed were studied using resistivity and Hall effect measurements from 10 to 300K. We found that for all the samples prepared by MEVVA implantation, as long as a continuous CoSi2 layer was formed after annealing, a strong temperature dependence of the Hall coefficient was observed with a large peak at around 90 to 110K. The magnitude of the peak also varies depending on the substrate parameters and processing conditions. However, the temperature dependence of the resistivity for these CoSi2 layers follows the atthiessen's rule. We also found that it does not require high substrate temperature nor very high temperature annealing in order to form a CoSi2 layers with low resistivity by MEVVA implantation. Such low resistivity CoSi2 layers can be formed with a substrate temperature as low as 210°C after either RTA at high temperature for a few seconds or FA at a relatively low temperature of 750°C for one hour. The dependence of the electrical properties on Ts is also presented and discussed.