Low Temperature Hydrophilic SiC Wafer Level Direct Bonding for Ultrahigh-Voltage Device Applications

Abstract

SiC direct bonding using O2 plasma activation is investigated in this work. SiC substrate and n− SiC epitaxy growth layer are activated with an optimized duration of 60s and power of the oxygen ion beam source at 20 W. After O2 plasma activation, both the SiC substrate and n− SiC epitaxy growth layer present a sufficient hydrophilic surface for bonding. The two 4-inch wafers are prebonded at room temperature followed by an annealing process in an atmospheric N2 ambient for 3 h at 300 °C. The scanning results obtained by C-mode scanning acoustic microscopy (C-SAM) shows a high bonding uniformity. The bonding strength of 1473 mJ/m2 is achieved. The bonding mechanisms are investigated through interface analysis by transmission electron microscopy (TEM) and energy dispersive X-ray spectroscopy (EDX). Oxygen is found between the two interfaces, which indicates Si–O and C–O are formed at the bonding interface. However, a C-rich area is also detected at the bonding interface, which reveals the formation of C-C bonds in the activated SiC surface layer. These results show the potential of low cost and efficient surface activation method for SiC direct bonding for ultrahigh-voltage devices applications.

Growth of telecom C-band In(Ga)As quantum dots for silicon quantum photonics

“…The as-grown sample surface exhibited a root-mean-square (RMS) roughness, R q of 0.18 nm from an atomic force microscopy (AFM) scan measured over a 20 × 20 µm 2 area. This value is well below the general roughness limit of 0.5 nm, which has to be satisfied to achieve successful direct bonding on a wafer-scale [25,26].…”

Study on the mechanism of glass-SiC-glass anodic bonding process

“…To meet the advancement of semiconductor industry, it is imperative to find a novel semiconductor material to meet the requirement. Silicon carbide [20][21][22][23] (SiC) as the third generation semiconductor material received increasingly concerns due to its excellent properties such as higher carrier saturation velocity [24], higher breakdown electric field [25], lager band gap [26] and higher mechanical hardness. In addition, SiC was almost transparent to the visible light [27] and operated in harsh environments (high-temperature and radioactive) [28].…”