Static Characteristics of n+-n-p-p+ Silicon IMPATT Diode

Abstract

To optimize device performance, theoretical analysis for static characteristics of an n+-n-p-p+ silicon IMPATT diode with a deep junction from the surface and a diffused junction in the n-p layer is presented. The doping profile in the (n) layer is considered to be
a Chebyshev orthogonal polynomial form, the diffusion coefficient is concentration-dependent, and the junction depth varies according to the diffusion time. The most important characteristics such as the electric field distribution, potential distribution, and
excess noise factor are treated numerically using Newton's method and the introduction of MATLAB version 6.1. Furthermore, response speed and the figure of merit, the CW output power, are treated. It is found that the electric field and the potential are both increased with increasing junction depth because of the increase in both the depletion layer width and the impurity gradient. The excess noise factor is enhanced with a deeper junction since the maximum field is at its highest value. The response speed and the output power are decreasing with wider depletion width and can be enhanced using moderate junction depth.