Study of Spatial Distortion in InP Nanophotonic Membranes on Different Carrier Substrates

Electron Beam Lithography (EBL) metrology and least-square estimation of wafer-scale distortions is used to determine InP membrane deformation as a result of bonding to different substrate materials. First, the accuracy of EBL as a metrology tool for this particular application was assessed. Next, modelling of distortions was tested on unbonded InP wafers as a reference for extracting post-bonding distortions. Then we investigated the effect of substrate material choice on InP membrane deformation after bonding. We found residual expansion factors of 4.53±1, 312.4±1, and 317±1 ppm of the InP membrane bonded to InP, Si, and 3C-SiC carriers, respectively. For the SiO
2
carrier, the 3inch InP membrane split into smaller membranes to reduce the stress, highlighting the importance of substrate choice.