A Review on Precision Polishing Technology of Single-Crystal SiC

Abstract

Single-crystal SiC is a typical third-generation semiconductor power-device material because of its excellent electronic and thermal properties. An ultrasmooth surface with atomic surface roughness that is scratch free and subsurface damage (SSD) free is indispensable before its application. As the last process to reduce the surface roughness and remove surface defects, precision polishing of single-crystal SiC is essential. In this paper, precision polishing technologies for 4H-SiC and 6H-SiC, which are the most commonly used polytypes of single-crystal SiC, such as chemical mechanical polishing (CMP), photocatalytic chemical mechanical polishing (PCMP), plasma-assisted polishing (PAP), electrochemical mechanical polishing (ECMP), and catalyst-referred etching (CARE), were reviewed and compared with emphasis on the experimental setup, polishing mechanism, material removal rate (MRR), and surface roughness. An atomically smooth surface without SSD can be obtained by CMP, PCMP, PAP, and CARE for single-crystal SiC. However, their MRRs are meager, and the waste treatment after CMP is difficult and expensive. Moreover, PAP’s operation is poor due to the complex polishing system, plasma generation, and irradiation devices. A high MRR can be achieved by ECMP. In addition, it is an environmentally friendly precision polishing process for single-crystal SiC since the neutral salt solution is generally used as the electrolyte in ECMP. However, the formation of the egglike protrusions at the oxide/SiC interface during anodic oxidation would lead to a bigger surface roughness after ECMP than that after PAP is processed. The HF solution used in CARE was toxic, and Pt was particularly expensive. Ultrasonic vibration-assisted single-crystal SiC polishing and electrolyte plasma polishing (EPP) were discussed; furthermore, the research direction of further improving the surface quality and MRR of single-crystal SiC was prospected.

Approach: developing nano/sub-micron diamond slurry technology for enhanced precision polishing of optoelectronic materials

“…The MRR of traditional CMP slurry using colloidal is very small and take a very long time as reviewed in Refs. 5, 9, 19, and 20. Several CMP slurries use metal additives to improve the polishing performance; however, the duration and complexity of using such methods make them unsuitable in most instances as compared to the current proposed method.…”

“…Similarly, lithium niobate (LiNbO 3 ) wafers have found extensive use in the field of photonics, particularly in integrated optics, telecommunications, and laser technology. [1][2][3][4][5] The rapid development of various electronic devices has led to an increased demand for high-quality and defect-free semiconductor wafers and epitaxial substrates. Achieving precise control over surface morphology and atomic-level surface roughness is crucial for determining the performance and reliability of these devices.…”

“…Similarly, lithium niobate (LiNbO3) wafers have found extensive use in the field of photonics, particularly in integrated optics, telecommunications, and laser technology 1 – 5 …”

Recent Advances In Silicon Carbide Chemical Mechanical Polishing Technologies

“…We also raise the importance of electrostatic interaction and how it affects CMP efficiency. As pointed out in the literature [ 23 ], integrating hybrid energies into the CMP system can be an effective approach to enhance oxidation efficiency as well as MRR. Therefore, in the following sections, we focus on recent advances in electro-CMP (ECMP) and photocatalyzed-CMP (PCMP) and their variants, such as Fenton-ECMP, ultrasonic-ECMP, sulfate-PCMP, gas-PCMP and Fenton-PCMP.…”

Damage prediction of sintered α‐SiC using thermo‐mechanical coupled fracture model

“…The material 𝛼-SiC is chosen due to its many applications, from abrasives to semiconductors. 20,21 Because of its high wear resistance and strength at high temperatures, 𝛼-SiC is also a leading candidate for use in thermal protection systems. 22 Therefore, the proposed framework is designed with a view towards 𝛼-SiC applications.…”