Monte Carlo analysis of a lateral IBIC experiment on a 4H-SiC Schottky diode

TL;DR

This study combines Monte Carlo simulations with electrostatic modeling to analyze charge collection efficiency in a 4H-SiC Schottky diode using IBIC, revealing detailed transport properties and device characteristics.

Contribution

It introduces a novel computational approach integrating finite element electrostatic solutions with Monte Carlo methods for IBIC data interpretation.

Findings

CCE plateau near 100% in depletion region

Diffusion dominates charge transport in neutral region

Accurate extraction of diffusion length and carrier lifetime

Abstract

The transport properties of a 4H-SiC Schottky diode have been investigated by the Ion Beam Induced Charge (IBIC) technique in lateral geometry through the analysis of the charge collection efficiency (CCE) profile at a fixed applied reverse bias voltage. The cross section of the sample orthogonal to the electrodes was irradiated by a rarefied 4 MeV proton microbeam and the charge pulses have been recorded as function of incident proton position with a spatial resolution of 2 um. The CCE profile shows a broad plateau with CCE values close to 100% occurring at the depletion layer, whereas in the neutral region, the exponentially decreasing profile indicates the dominant role played by the diffusion transport mechanism. Mapping of charge pulses was accomplished by a novel computational approach, which consists in mapping the Gunn's weighting potential by solving the electrostatic problem by finite element method and hence evaluating the induced charge at the sensing electrode by a Monte Carlo method. The combination of these two computational methods enabled an exhaustive interpretation of the experimental profiles and allowed an accurate evaluation both of the electrical characteristics of the active region (e.g. electric field profiles) and of basic transport parameters (i. e. diffusion length and minority carrier lifetime).