High Density Integration of Single Crystal Thin Film Devices by "Epifilm Bonding" Technology

Abstract

Bonding of single crystal thin film ("epifilm") by intermolecular-force ("epifilm bonding" (EFB)) has been investigated from view point of high-density integration of LEDs on dissimilar material substrates. Several bonding layers having different surface-roughness (Rpv) have been tested. Test result showed that EFB state on the bonding layer with Rpv~1nm was much better than those on bonding layers with Rpv >> 1nm; smooth surface of Rpv~1nm is preferable to achieve good EFB state. Diamond-like carbon (DLC) thin film with Rpv~1nm by chemical-vapor-deposition has been also tested as the bonding layer. Good EFB state on the DLC thin film has been achieved by optimizing of surface activation of the DLC thin film. EFB on the DLC thin film having higher thermal conductivities will be promising for high-density device-integration to obtain higher heat-dissipation and better device performance.