Impact of Temperature on Electrical Performance of Ni film on n-type 4H-SiC Contacts in Terms of Micropipes Density

Silicon carbide (SiC) is novel semiconductor material which is intensively studied recently due to its outstanding physical and electrical characteristics. One of the drawbacks of this innovative SiC material is the micropipe defect, which is created during SiC crystal growth. These defects worsen the performance of the semiconductor devices by increasing leakage current and decreasing breakdown voltage. As heat treatment is a necessary process in making Ohmic contact, it is interesting to examine the correlation between defects density and heating temperature. Nickel (Ni) films are deposited on n-type 4H-SÌC substrate to test for this correlation. Temperature up to 1000°C is used for heat treatment While it is still possible to form Ohmic contact with high-micropipe density samples (-100 micropipe per cm2), the impact of temperature on low-micropipe density samples (< 30 micropipe per cm2) is minor.