Room-temperature wafer bonding of SiC–Si by modified surface activated bonding with sputtered Si nanolayer

Abstract

A modified surface activated bonding (SAB) with Fe–Si multi-nanolayers is expected to achieve the wafer bonding of SiC to various materials. However, Fe diffusion, which affects device performance, cannot be avoided during some annealing processes. In this work, the room-temperature wafer bonding of SiC–Si by only one sputtered Si nanolayer was successfully achieved. The bonding interface was investigated. A uniform intermediate layer with a thickness of ∼15 nm just containing Si, C, and Ar was found at the interface. The bonding strength between the SiC surface and the sputtered Si nanolayer could reach the bulk Si strength in accordance with the results of the strength test. This indicates that the wafer bonding of SiC to any other materials can be achieved easily if the material could be also strongly bonded to the sputtered Si nanolayer. In addition, the thermal and chemical reliabilities of the SiC–Si bonding interface were investigated by rapid thermal annealing and KOH etching, respectively.

Progress in wafer bonding technology towards MEMS, high-power electronics, optoelectronics, and optofluidics

“…However, SAB is not useful for the bonding of insulators, such as SiO 2 and Si 3 N 4 . [68] Therefore, Tadatomo Suga et al from The University of Tokyo have developed a modified SAB method with Fe-Si nanolayers. [73] The modified SAB has been considered to realize the SiC wafer bonding with any other substrates.…”

“…Applying Si as proof of sample, the detailed bonding process is shown in Figure 3(a). [68] Firstly, the Ar atom or ion beam is used to remove the oxide layer and contaminations from the SiC wafer surface. Secondly, a nanometer-scale ($10 nm) Si layer is deposited on the SiC wafer surface by the sputtering with the Si target.…”

“…(a) Schematic diagram of the modified SAB. [68] (b) SAM image of the SiC/Si bonded pair. [68] (c) Blade test for the bonded pair.…”

“…[68] (b) SAM image of the SiC/Si bonded pair. [68] (c) Blade test for the bonded pair. [68] (d) TEM image of the SiC/Si bonding interface.…”

“…[68] (c) Blade test for the bonded pair. [68] (d) TEM image of the SiC/Si bonding interface. [68] (e) Schematic diagram for the anodic bonding of SiC and glass.…”