Papers by Author: Kin Kiong Lee

Abstract: In this paper we give a comparative study of two types of gate oxidation of n-channel 6HSiC MOSFETs. One set of transistors was fabricated using pyrogenic oxidation with no postoxidation annealing, and for the second set the oxide was grown in dry O2 with post-oxidation annealing. The lateral MOSFETs show a Hall mobility of ~ 75 cm2/Vs which is essentially same for both types of oxide. From the IV characteristics curves, the latter devices exhibit an average effective channel mobility of 72 (± 5) cm2/Vs, whereas the former has a value of 30 (± 3) cm2/Vs. From the capacitance and conductance measurements, the interface trap density for pyrogenicgrown oxide using is roughly a factor of 2 greater than those grown by dry oxidation. We found that the pyrogenic post-oxidation anneal at 1073K helps to reduce the interface states density and improves the effective channel mobility of 6H-SiC MOSFETs.

Abstract: This paper studies the electronic properties of MOS capacitors fabricated on double positioning boundary free 3C-SiC/6H-SiC where the 3C-SiC films were grown using the Vapour- Liquid-Solid mechanism. The temperature- and frequency-dependent electrical properties of SiO2/3C-SiC/6H-SiC structures have been studied. Capacitance measurements indicate that the single-domain 3C-SiC film is doped near the surface with an average concentration of 8.3 × 1016 cm-3. The measured interface state density near the conduction band edge of 3C-SiC is below 1011cm-2⋅eV-1 and increases towards mid-gap as obtained from conductance and capacitance measurements. Our results are consistent with the assumption that the interfaces of SiO2/ n-type SiC consist of two different kinds of interface traps – the carbon clusters located at the interface and the intrinsic defects located within the oxide layer.