Effects of the epitaxial layer thickness on the noise properties of Schottky barrier diodes

Abstract

An analytical theory to describe the combined effects of the epitaxial layer thickness and the ohmic contact on the noise properties of Schottky barrier diodes is presented. The theory, which provides information on both the local and the global noise properties, takes into account the finite size of the epitaxial layer and the effects of the back ohmic contact, and applies to the whole range of applied bias. It is shown that by scaling down the epitaxial layer thickness, the current regime in which the noise temperature displays a shot-noise-like behavior increases at the cost of reducing the current range in which the thermal-noise-like behavior dominates. This improvement in noise temperature is limited by the effects of the ohmic contact, which appear for large currents. The theory is formulated on general trends, allowing its application to the noise analysis of other semiconductor devices operating under strongly inhomogeneous distributions of the electric field and charge concentrations.

Shot-noise suppression in Schottky barrier diodes

“…Microscopic approaches at hydrodynamic 3,4 and kinetic levels 5,6 confirm the above expression without resorting to two independent noise sources, but providing a selfconsistent solution of the dynamics together with the Poisson equation. However, a physical interpretation of the noise properties of SBD, and in particular of the crossover between shot and thermal noise, is still lacking in the current literature and constitutes an intriguing question.…”

“…To obtain their statistical properties one needs to compute explicitly the electric field fluctuations. 3,4 For this communication it is enough to notice that ␦I E (t) is negligible when H(x) is constant ͑or nearly constant͒, since then ␦I E (t)ϷH͐ 0 L dx␦E x (t) ϭH␦V(t)ϭ0, where current fluctuations are calculated under fixed bias conditions. ͑iii͒ The term involving ␦I D (t) represents the current fluctuations due only to diffusion processes since it is directly related to the fundamental diffusion noise source, ␦I x (t).…”

Epilayer Thickness and Doping Density Variation Effects on Current-Voltage (I-V) Characteristics of n-GaN Schottky Diode

“…An important problem in this respect is to understand the role played by the epitaxial layer thickness. The epitaxial layer thickness and doping density has considerable effects on the current operation of devices [1]. The main design variables that affect the schottky barrier diodes performance are the contact metal work function, the epilayer doping, epilayer thickness [2].…”

“…An increase in doping or a decrease in thickness from the designed values will affect the reverse characteristics and breakdown voltage. The doping density can be related to this voltage as [2]: ND=,E2CR/2qVBR (1) Here g, is dielectric permittivity, Ecr is critical field, VBR breakdown voltage. The epilayer thickness is critical in determining the reverse breakdown voltage as follows [2]: tepi=2VBR/Ecr (2) Here Er is the critical field of semiconductor, VBR is breakdown voltage, tepi epilayer thickness.…”

Impedance field and noise of submicrometer n+nn+ diodes: Analytical approach

“…The effectiveness of this technique has been demonstrated on various nonhomogeneous structures such as n ϩ n homojunctions, 5,6 Schottky barrier contacts, 7 and Schottky diodes. 8 The aim of this article is to apply the DD framework to the local noise analysis of submicron n ϩ nn ϩ diodes and to obtain in a closed analytical form the impedance field and the local noise characteristics. In long diodes ͑տ1m͒, the diffusive part of the current may be neglected and only the drift part is usually considered.…”