Compound semiconductor interfaces obtained by direct wafer bonding in hydrogen or forming gas

A technique of direct bonding wafers up to 6-inch diameter without mechanical load after being heated to elevated temperatures in H2 or in non-flammable forming gas (5% H2/95% N2) was applied to GaAs and GaAs/GaP. Electron microscopy revealed crystallographic bond interfaces containing the typical dislocation network. The density of dislocations can be easily chosen below a limit adverse to electrical properties. Current–voltage characteristics of doped GaAs wafer pairs showed ohmic behavior of p–p and n–n junctions, whereas p–n diodes showed 2 to 3 V breakdown voltage as well as an ideality factor between 1.0 and 1.8.