High voltage, temperature-hard 3C-SiC Schottky diodes using all-Ni metallization

Abstract

High voltage Schottky diodes have been fabricated on 3C-Sic films grown on Si substrates. A Ni metallization process has been developed to fabricate both rectifying and ohmic contacts to Sic by controlling the postannealing temperature. A high voltage (>150V) breakdown has been obtained at room temperature from the Sic Schottky diode. The Ni-Sic Schottky junction shows a thermal resistance for temperatures as high as 600°C. This technology has good potential for monolithic integration of Sic high power devices and Si integrated circuits.

High-voltage Ni- and Pt-SiC Schottky diodes utilizing metal field plate termination

“…Our objective was to operate the diodes at high temperatures (at least 300 C) and our preliminary studies [9], [10] as well as reports from other researchers [19] had shown that Ni results in suitably large barrier heights (1.2-1.3 eV) to SiC. Thus, we have utilized this metal extensively to study high-voltage Schottky rectifiers on 4H-and 6H-SiC for hightemperature applications.…”

“…Applying (7), can be deduced as (10) The plot of versus thus gives a straight line which intercepts the axis at . Using the ideality factor value extracted from the vs. plot, the barrier height can be determined.…”

“…In addition, the oxide layer grown serves two other purposes 1) surface passivation; and 2) removal of surface defects from the SiC layer which upon oxidation is etched off from the areas where the Schottky contact is to be formed. We first reported this structure for fabricating highvoltage SiC Schottky diodes in 1993 [9], [10], and since then we have consistently achieved good results with this approach [11]- [15]. We were also the first to utilize Ni for both Schottky and ohmic contact due to its refractory nature (allowing hightemperature operation), and large barrier height to 3C-SiC [9], [10], 6H-SiC [11]- [13], and 4H-SiC [14], [15].…”

“…We first reported this structure for fabricating highvoltage SiC Schottky diodes in 1993 [9], [10], and since then we have consistently achieved good results with this approach [11]- [15]. We were also the first to utilize Ni for both Schottky and ohmic contact due to its refractory nature (allowing hightemperature operation), and large barrier height to 3C-SiC [9], [10], 6H-SiC [11]- [13], and 4H-SiC [14], [15]. The use of metals such as Ni that form a large barrier height on SiC allow operation of diodes at higher temperature with lower power losses compared to metals such as Ti which have relatively smaller barrier height to SiC, as discussed later.…”

Analysis of Punch-Through Breakdown Voltages in 3C-Sic Schottky Barrier Diode Using Gaussian Profile for 200µm Thick Wafer

“…High voltage Schottky diodes were fabricated on 3C-SiC films grown on Si substrates in 1993. A Ni metallization process was developed to fabricate both rectifying and ohmic contacts to SiC by controlling the post annealing temperature [5]. The characteristics of vertical Schottky barrier diodes (SBD) fabricated on N /N + 3C-SiC grown on N + Si substrate were reported in 1994 [6].…”