Germanium on Sapphire

Abstract

This paper explores the potential of germanium on sapphire (GeOS) wafers as a universal substrate for System on a Chip (SOC), mm wave integrated circuits (MMICs) and optical imagers. Ge has a lattice constant close to that of GaAs enabling epitaxial growth. Ge, GaAs and sapphire have relatively close temperature coefficients of expansion (TCE), enabling them to be combined without stress problems. Sapphire is transparent over the range 0.17 to 5.5 µm and has a very low loss tangent (α) for frequencies up to 72 GHz. Ge bonding to sapphire substrates has been investigated with regard to micro-voids and electrical quality of the Ge back interface. The advantages of a sapphire substrate for integrated inductors, coplanar waveguides and crosstalk suppression are also highlighted. MOS transistors have been fabricated on GeOS substrates, produced by the Smart-cut process, to illustrate the compatibility of the substrate with device processing.

Self‐Powered Photodetector Based on Perovskite/Ge Heterojunction with High Responsivity

“…With an appropriate diffusion rate, FAPbBr 3 SC with high quality was obtained and heterojunction with tight combination was formed. Additionally, the crystal structures of FAPbBr 3 SC and Ge are both cubic systems with lattice constants of 6.00 and 5.66 Å, [20,21] respectively. The difference of lattice constants is tolerant to heteroepitaxial growth of FAPbBr 3 SC indicated by the crystal growth kinetic.…”

Investigation of Germanium Implanted with Hydrogen for Layer Transfer Applications

“…Low temperature wafer bonding is employed to join the germanium wafer to the handle wafer. This technology has been described elsewhere [2]. In order to produce a thin Ge layer, the wafer is ion implanted with hydrogen.…”

Carrier Mobility Variations in Self-Aligned Germanium MOS Transistors

“…Since silicon dioxide is the primary gate dielectric material in early germanium MOS devices (2,3), it was used as the dielectric for this investigation. Previous experiments suggest that it provides a good interfacial quality with bulk germanium and achieves MOS transistors with high mobility (2)(3)(4). SiO 2 can also be employed as the dielectric at the back interface for non double-gated GeOI devices.…”