The effects of high-energy proton irradiation on the electrical characteristics of Au/Ni/4H-SiC Schottky barrier diodes

Abstract

Au/Ni (20:80) Schottky barrier diodes (SBDs) were resistively evaporated on nitrogen-doped n-type 4H-SiC. Current-voltage (I-V) and capacitance-voltage (C-V) characteristics of the SDBs were investigated before and after bombardment with 1.8 MeV proton irradiation at a fluence of 2.0 × 10 12 cm -2 . The measurements were carried out in the temperature range 40 -300 K in steps of 20 K. Results obtained at room temperature (300 K) showed highly rectifying devices before and after bombardment. It was observed that the proton irradiation induced an increase of ideality factor from 1.05 to 1.13, a decrease in Schottky barrier height from 1.40 to 1.22 eV, an increase in series resistance from 10 to 66 Ω and a noticeable increase of the saturation current from 3.0 × 10 -21 to 6.8 × 10 -17 A. The increase in saturation current after proton irradiation was attributed to the presence of interfacial states created by irradiation-induced defects. Thermionic emission dominated the I-V characteristics in the temperature range 120 -300 K but the I-V characteristics deviated from thermionic emission theory at temperatures below 120 K for devices both before and after irradiation. The variation of the SBDs characteristics with temperature was attributed to the presence of lateral inhomogeneities of the SBH. Modified Richardson constants were determined from a Gaussian distribution of barrier heights to be 133 and 165 A cm -2 K -2 before and after irradiation, respectively.

Electrically active induced energy levels and metastability of B and N vacancy-complexes in 4H–SiC

“…The different polytypes of SiC only differ in the stacking order which affects their electronic and optical properties. Earlier reports have shown that all polytypes are inert, hard and have high thermal conductivity [1,2]. Furthermore, the breakdown electric field strength, saturated drift velocity or impurity ionization energies are all specific for different polytypes.…”

“…The 4H-SiC is a promising material for high-voltage devices due to its higher bulk mobility and smaller anisotropy compared to other polytypes. The 4H-SiC has been experimentally reported to have a wide band gap of 3.26 eV at 300 K. In addition, the 4H-SiC is capable of operating at high temperature and high frequency which makes it a suitable substrate mat erial for producing high frequency electronic devices for applications in radiation harsh environments (space, accelerator facilities and nuclear power plants) [1,2]. Point and extended defects play vital roles in 4H-SiC as they have the tendency to either influence or limit its performance.…”

“…The study of radiation-induced defects in semiconductors is a significant area of research in material science from the point of view of device applications [3]. Defects in 4H-SiC semiconductor and its electrically active levels along with the stability within the band gap have been studied experimentally [1,3,4] or theoretically [5][6][7]. Some of these defects are thermodynamically stable whereas some are unstable.…”

Medium Energy Carbon and Nitrogen Ion Beam Induced Modifications in Charge Transport, Structural and Optical Properties of Ni/Pd/n-GaN Schottky Barrier Diodes

“…The transport of carriers across the M-S interface is influenced by the junction barrier potential. Therefore, it is of significant importance to study the current transport properties of the M-S interface and its modification for a better understanding of the operations of electronic devices [3,4].…”