Investigation of Doping Techniques on the Silicon Based Capacitor

This technical paper investigates the effect of doping techniques, type of dopant species and the plate size on the capacitance density of a silicon based capacitor. The substrate of the silicon wafers are highly doped using either solid source (SS) or spin-on dopant (SOD) method. Experiments are carried out at three different diffusion temperatures, 900oC, 1000oC and 1050oC. Results show that the diffusion by spin-on dopant gives a higher capacitance density compared to diffusion by solid source while larger plate size leads to a larger capacitance value. In addition, the experiment also shows that n-type wafer heavily doped with phosphorus exhibits a higher capacitance density.