Materials Science Forum, Vol.389-3, 1363-1366, 2002
Influence of semi-insulating substrate purity on the output characteristics of 4H-SiC MESFETs
The aim of this work is to study the influence of the semi-insulating (SI) substrate purity on the electrical characteristics of 4H-SiC MESFETs. Two types of SI substrates have been used. The first ones are substrates grown by physical vapor transport (PVT) purchased from CREE Research. The second ones are substrates grown by HTCVD purchased from OKMETIC. For all the transistors, I-ds-V-ds measurements as a function of temperature have first been performed. Different parasitic effects on the static output characteristics are observed in the case of PVT substrates. Frequency dispersion of the output conductance have next been realized showing the presence of deep traps with activation energy around 1 eV for transistors realized on PVT substrates. In the case of HTCVD substrates none of the above parasitic effects depicted above have been observed.