Correlation between Defects and Electrical Performances of Ion-Irradiated 4H-SiC p-n Junctions.

Domenico Pellegrino,Lucia Calcagno,Salvatore Di Franco,Antonella Sciuto,Massimo Zimbone

doi:10.3390/ma14081966

Domenico Pellegrino, Lucia Calcagno + Show 3 more

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https://doi.org/10.3390/ma14081966

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Abstract

In this study, 4H-SiC p–n junctions were irradiated with 700 keV He+ ions in the fluence range 1.0 × 1012 to 1.0 × 1015 ions/cm2. The effects of irradiation were investigated by current–voltage (I–V) and capacitance–voltage (C–V) measurements, while deep-level transient spectroscopy (DLTS) was used to study the traps introduced by irradiation defects. Modifications of the device’s electrical performances were observed after irradiation, and two fluence regimes were identified. In the low fluence range (≤1013 ions/cm2), I–V characteristics evidenced an increase in series resistance, which can be associated with the decrease in the dopant concentration, as also denoted by C–V measurements. In addition, the pre-exponential parameter of junction generation current increased with fluence due to the increase in point defect concentration. The main produced defect states were the Z1/2, RD1/2, and EH6/7 centers, whose concentrations increased with fluence. At high fluence (>1013 ions/cm2), I–V curves showed a strong decrease in the generation current, while DLTS evidenced a rearrangement of defects. The detailed electrical characterization of the p–n junction performed at different temperatures highlights the existence of conduction paths with peculiar electrical properties introduced by high fluence irradiation. The results suggest the formation of localized highly resistive regions (realized by agglomeration of point defects) in parallel with the main junction.

Highlights

IntroductionSilicon carbide (SiC) has received much attention in recent years due to its large bandgap, high thermal conductivity, high breakdown field, and electron mobility [1]
investigated by current– voltage (I–V) were governed by the important nation current, while in the latter, the series resistance of the diode was the more recombination current,aswhile in discussed the latter, later the series parameter, will be on. resistance of the diode was the more important parameter, as will be discussed later on
The rectification ratio calculated at a bias of ±3.5 V was 5 × 108 in the un-irradiated and in the low fluence-irradiated diodes, while it decreased to about 2 × 107 in the higher fluence diodes, evidencing the significant degradation of diode rectifying properties

Summary

Introduction

Silicon carbide (SiC) has received much attention in recent years due to its large bandgap, high thermal conductivity, high breakdown field, and electron mobility [1]. All these properties make SiC an ideal material for high-power and high-frequency devices and, more generally, for the fabrication of harsh-environment electronics [2,3]. Other properties such as biocompatibility, visible blindness, and radiation hardness make this material attractive for alternative applications, such as biomedical sensors, as well as for UV and X-ray functions, charged particle detectors [4,5,6,7], and for uses involving visible radiation presences, such as plasma environments [8,9]

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