Fabrication of a bonded LNOI waveguide structure on Si substrate using ultra-precision cutting

Abstract

The heterogeneous integration of an LNOI waveguide device on a mature Si platform is interesting for the creation of a future high density and multi-functional platform. This paper reports the fabrication of a bent LNOI waveguide on Si substrate using surface activated bonding with a Si nanoadhesive layer and post-bond ultra-precision cutting at room temperature. This bonding method demonstrates the sufficient bond strength between an LN wafer and thermally grown SiO 2 to withstand ductile-mode cutting for waveguide fabrication. In this work, the width, height, and bent radius of the ridged LNOI waveguide on Si substrate were approximately 5, 2.5, and 300 μm, respectively. These room-temperature bonding and cutting methods are expected to fabricate various heterogenous devices with a large coefficient of thermal expansion mismatch between dissimilar materials, not just LNOI/Si waveguide devices.

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

“…[95] Perfect bonding and dicing samples are shown in Figure 4(j). [96,99] The smooth LiNbO 3 waveguide will also show a low-loss light propagation. Therefore, it is feasible to fabricate the LiNbO 3 thin films by the wafer-level direct bonding method.…”

“…[95] (l) The physical image of the direct LiNbO 3 /SiO 2 bonding interface. [96] (m) SEM image of the bonded LNOI waveguide. [97] consists of a slab and a strip superimposed onto it, as shown in Figure 5(a).…”

Room-Temperature Bonding of Indium Phosphide Wafers and Their Atomic Structure at the Bond Interface

“…A Si atomic layer can be a good alternative in this regard, as it is highly transparent over a wide range of infrared wavelengths. Meanwhile, a bonding method using an activated Si atomic layer was demonstrated to be effective for improving the bond strength in the bonding of oxide materials. ,− It might be interesting to apply both SAB and bonding using an activated Si atomic layer for the bonding of InP wafers. Moreover, it would be meaningful to analyze the effect of bonding and observe the state of the bond interface for investigating the mechanism of the room-temperature bonding of InP.…”

Investigation of the interface between LiNbO3 and Si fabricated via room-temperature bonding method using activated Si nano layer

“…The bonding of LiNbO 3 and Si using the SAB method has been previously reported. 9,18) In addition, bonding methods have recently been developed that employ activated metal [23][24][25][26] or Si [27][28][29][30][31][32] as an adhesive layer.…”