Fabrication of Ohmic Contact on N-Type SiC by Laser Annealed Process: A Review

Abstract

In recent years, because of stringent needs in the fabrication of silicon carbide (SiC) power devices, laser annealing has been introduced to achieve local ohmic contact. In this paper, the laser annealing research for the ohmic contact process of SiC power devices is reviewed, which is mainly divided into four aspects: laser process mechanism, ohmic contact electrode materials, and substrate materials. The effect of laser parameters on ohmic contact and the annealing process on SiC diode devices is also reviewed. Progress of other substrate materials, namely 6H-SiC and semi-insulating 4H-SiC-based devices with laser annealed ohmic contacts, is also briefly discussed, in which formation of semi-insulating SiC ohmic contacts is derived from laser irradiation at the interface to produce 3C-SiC. Some experiment results have been shown in the passage, such as XRD, SEM, TEM, etc. In the review, it points out that the direction of application and development of the laser annealing process for improving the ohmic contact of SiC power devices is highly encouraging.

Improvement of β-SiC Synthesis Technology on Silicon Substrate

“…In addition to its robust thermal conductivity, electric breakdown voltage, and current density, SiC can operate over a broad temperature range without undergoing degradation in its monocrystalline structure or phase transitions. Through doping, the semiconductor properties of SiC can be tailored to yield both n-type and p-type materials [36,37]. These defects have been reported to impede the electrical and mechanical properties of the material, as corroborated by extensive studies [38,39].…”

Resistor-to-Schottky barrier analytical model for ohmic contact test structures

“…Forming ohmic contacts requires high-temperature annealing, which activates the implanted dopants and forms silicide layers in traditional silicon ohmic contacts [8]. Recent advances in annealing, such as laser thermal annealing (LTA), have resulted in superior ohmic contacts for 4H-SiC-based devices [9] and up to 16% reduction in contact resistivity for Sub-10 nm FinFETs [10]. Improved models for ohmic contacts would be valuable in guiding future process refinements.…”

Silicon and Silicon Carbide Recrystallization by Laser Annealing: A Review

“…Laser thermal annealing is an ultrafast and low thermal budget process solution for the passivation of backside illuminated sensors and power devices. Laser annealing can be a solution for the backside contact of those chips with a vertical flow of electrical current, where an ohmic contact and/or collector on the wafer backside are required [9,10], including SiC power Metal-Oxide-Semiconductor Field Effect Transistors (MOSFET) [11], Insulated Gate Bipolar Transistor (IGBT) [12], and high voltage diodes [13,14]. Moreover, this process can also be useful for the ohmic contact formation process in SiC Schottky diodes, causing a negligible impact on the device's front side [15,16].…”