Transferring of thick active optical components via the method of tetherless micro-transfer printing

Among the various approaches to heterogeneous integration, micro transfer printing (MTP) is a practical and emerging heterogeneous integration method. Typically, the components integrated by MTP are thin-film components and the process of MTP usually requires a sacrificial layer and materials like photo resists as tethers to fix the components. In this work, we demonstrate a tetherless MTP method. We built a complete setup for MTP. We use this setup and a flexible thin-film PDMS stamp with micro-structures as a transfer medium to directly pick up active optical components from a dicing tape with ejector assistance, and then print them directly onto a silicon wafer substrate without any adhesive. And we only require van der Waals force to complete the entire MTP process. Experiments have demonstrated that this method can transfer active optical components of various sizes and thicknesses without contamination and the performance parameters of these components are not affected. The responsivity of avalanche photo diode tested by the manufacturer is 0.9A/W and tested after being transferred at -25V bias is 0.83 A/W. The dark current of the device after being transferred is 13nA at a bias of -13V, which is similar to the value tested by the manufacturer, both at the nanoampere level. We have also attempted to use this new MTP method to transfer an array of semiconductor optical amplifiers, which provides a way to transfer a large number of optical components of various sizes and thicknesses for the practical implications of product packaging and product’s application.