Electrical characterization and modeling of SiC IC test structures

Abstract

Ohmic contacts and resistor structures have been evaluated for a 4HSiC ECL technology. Sheet resistance, contact resistance, transfer length and specific contact resistivity have been measured with the linear transfer length method. Values for such parameters are reported for each layer of npn bipolar junction transistors in the temperature range from 27 to 300 C. Sheet resistance exhibits a 60% decrease with increasing temperature in the p-type layer, while a non-monotonous dependence is found for the ntype layers, with values spreading in a range which is wide about 10% the room temperature value. Strip and serpentine integrated resistors have also been tested. Simulations of sheet resistance for n- and p-type layers are compared to experimental data. Different sources for incomplete ionization and mobility are considered. A good agreement is finally found for the ptype layer, while the need to model the metal-non-metal transition arises in the n-type layer