Revisiting the analytic theory of p-n junction impedance: Improvements guided by computer simulation leading to a new equivalent circuit

Authors
Citation
Se. Laux et K. Hess, Revisiting the analytic theory of p-n junction impedance: Improvements guided by computer simulation leading to a new equivalent circuit, IEEE DEVICE, 46(2), 1999, pp. 396-412
Citations number
26
Categorie Soggetti
Eletrical & Eletronics Engineeing
Journal title
IEEE TRANSACTIONS ON ELECTRON DEVICES
ISSN journal
00189383 → ACNP
Volume
46
Issue
2
Year of publication
1999
Pages
396 - 412
Database
ISI
SICI code
0018-9383(199902)46:2<396:RTATOP>2.0.ZU;2-S
Abstract
We revisit the analytic derivation of the de and low frequency ac behavior of the p-n step junction and suggest all preexisting treatments are flawed for three important reasons, First, not all contributions to the diode curr ent are included. We derive a rigorous expression for each component of cur rent that can be used to judge the completeness of existing analytic theori es. Additionally, wrong boundary conditions for minority carrier concentrat ions and incorrect equivalent circuit topologies undermine present analytic theories of the diode. We propose a new analytic equivalent circuit model which institutes correct boundary conditions. The resulting circuit model d emonstrates excellent de and ac accuracy for symmetric and asymmetric junct ions, for long, short, or intermediate base regimes, Inductive behavior ass ociated with short base diodes at large forward bias is reproduced, as is t he decrease in capacitance observed in long base diodes. The assumptions an d limitations of our new circuit model are thoroughly investigated.