Injection ratio and storage time of a non-uniformly doped Schottky barrier diode

The minority carrier injection and excess minority carrier stored charge of a non-uniformly doped n-Si Schottky barrier diode (SBD) considering carrier recombination and blocking properties of the low-high (n^-n⁺) interface are analysed in this work. Based on the result of numerical analysis of slow variation of minority carrier current within the quasi-neutral Si, minority carrier current density is represented by a polynomial, and using that equation a solution of minority carrier profile is obtained. For the first time, a closed form expression for minority carrier profile p(x) for non-uniformly doped n-Si SBD is obtained, which is applicable for all levels of injection. Storage time and injection ratio can be obtained from minority carrier profile. Present analysis shows that charge storage time and current injection ratio depend on peak doping density, N_o and the logarithmic slope of doping profile, α. The storage time and injection ratio increase with α and decrease with increase of N_o. The results for Storage time and injection ratio obtained numerically, together with those obtained using the present model are compared and both results are found in good agreement.