Strain analysis of InP/InGaAsP wafer bonded on Si by X-ray double crystalline diffraction

Wafer bonding between p-Si and an n-InP-based InGaAsP multiple quantum well (MQW) wafer was achieved by a direct wafer bonding method. In order to investigate the strain at different annealing temperatures, four pre-bonded pairs were selected, and pair one was annealed at 150 °C, pair two at 250 °C, pair three at 350 °C, and pair four at 450 °C, respectively. The macroscopical strains on the bonded epitaxial layer include two parts, namely the internal strain and the strain caused by the mismatching of the crystalline orientation between InP (1 0 0) and Si (1 0 0). These strains were measured by the X-ray double crystalline diffraction, and theoretical calculations of the longitudinal and perpendicular thermal strains at different annealing temperatures were calculated using the bi-metal thermostats model, both the internal strain and the thermal strain increase with the annealing temperature. Normal thermal stress and the elastic biaxial thermal strain energy were also calculated using this model.