Tailored Al2O3/4H-SiC interface using ion implantation
Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
The effects of ion implantation of Al2O3interface to 4H-SiC epitaxial n- and p-type layers are presented. Different fluencies of carbon and nitrogen ions are used, as well as different annealing processes, with the aim to study the effects of implanted ions at the Al2O3/SiC interface. Capacitance-Voltage (C-V) behavior for fabricated MOS capacitors is studied before and after implantation to determine the effect of the implantation. Terman‟s method was employed to extract the density of interface traps (Dit) present at the Al2O3/SiC interface. Effective oxide charges density (Neff), present inside the Al2O3,was also evaluated by comparing the theoretical (ideal) C-V curve with the experimental C-V curves.
It is generally known, and also proved by this study, that Al2O3 on n-type 4H-SiC shows significantly higher effective oxide charges density (Neff) and density of interface traps (Dit=3-4×1012 eV-1cm-2) compared to n-type SiO2/SiC MOS capacitors. However, the analysis of the collected data from N and C implanted n-type Al2O3/SiC samples show Dit values around 2-9×1011 eV-1cm-2, i.e., an effective reduction has been achieved by the ion implantation. The values of Neff for N ion implanted n-type Al2O3/SiC is as high as 1013 cm-2 in some cases, but C implanted n-type Al2O3/SiC sample shows exceptionally low Neff =1.8×1011 cm-2, which is comparable to SiO2/SiC based MOS capacitor. This result suggest that using C ion implantation before the formation of the oxide layer could be a promising approach to improving both oxide and interface properties of n-type 4H-SiC MOS capacitors.
Place, publisher, year, edition, pages
2011. , 47 p.
Engineering and Technology
IdentifiersURN: urn:nbn:se:kth:diva-90233OAI: oai:DiVA.org:kth-90233DiVA: diva2:504573
Subject / course
Microelectronics and Applied Physics
Master of Science - Nanotechnology
Hallén, Anders, Professor