SAIP2017

Electrical characterization of deep level defects created by bombarding the n-type 4H-SiC with 1.8 MeV proton irradiations

4 Jul 2017, 15:00

20m

A403A (Engineering Building 51)

Oral Presentation Track A - Division for Physics of Condensed Matter and Materials Physics of Condensed Matter and Materials 1

Speaker

Dr Ezekiel Omotoso (University of Pretoria, Pretoria, South Africa)

Description

We have characterized the deep level defects present before and after proton irradiation and annealing of n-type, N-doped, 4H-SiC using deep level transient spectroscopy (DLTS). The bombardment of the sample was carried out at fluence of 1.0 × 1012 cm–2. The suitability of Schottky barrier diodes (SBDs) was tested before and after proton irradiation and annealing by current–voltage (I-V) and capacitance–voltage (C-V) carried out at room temperature. I-V and C-V results revealed a degradation of the (SBDs) properties after proton irradiation. Rectification properties of the SBDs were restored gradually after annealing in flowing argon at temperatures varies from 125 to 625 °C. Presence of four electron traps (Ec – 0.10, Ec – 0.13, Ec – 0.18 and Ec – 0.69 eV) were observed in as-grown diodes. Deep level defects, Ec – 0.42 and Ec – 0.76 eV, were revealed after annealing the proton-irradiated SBDs up to 225 °C, while Ec – 0.42 eV later annealed out at 425 °C which led to changes in the spectrum shown in Fig. 1. The disappearance of Ec – 0.42 eV also probably led to the appearance of two electron traps (Ec – 0.31 and Ec – 0.62 eV) at annealing temperature of 425 °C. We speculate that the defect Ec – 0.42 eV has a link or relationship with defects Ec – 0.31 and Ec – 0.62 eV, respectively. The defects, Ec – 0.31 eV, remained up to high temperature annealing, has a similar energy with defect Ec – 0.32 obtained after electron irradiation, though unstable, which has been attributed to a carbon interstitial.

Level for award<br>&nbsp;(Hons, MSc, <br> &nbsp; PhD, N/A)?

N/A

Apply to be<br> considered for a student <br> &nbsp; award (Yes / No)?

No

Would you like to <br> submit a short paper <br> for the Conference <br> Proceedings (Yes / No)?

Yes

Main supervisor (name and email)<br>and his / her institution

Prof. W.E. Meyer
University of Pretoria

Summary

Proton irradiation with 1.8 MeV introduced deep level defects into thermally fabricated Ni/4H-SiC. These defects emanated were characterized by deep level transient spectroscopy. Annealing the irradiated devices revealed the presence of two new defects.