Epitaxial Regrowth of Ge on SGOI and GeOI Substrates Obtained by Ge Condensation

In this paper, we have investigated the influence of process parameters (bake temperature, bake duration and growth temperature) on the morphology of GeOI substrate thickened by Ge epitaxial regrowth. We have seen that the optimum bake temperature in terms of layer roughness and interfacial contamination is 600°C. For higher bake temperatures, the layer morphology is 3D due to a layer dewetting. The efficiency of the surface preparation prior to the epitaxial regrowth has been assessed by Angle resolved X-Ray Photoelectrons Spectroscopy. No residual oxygen contamination has been detected. Furthermore, we have investigated the influence of the growth temperature on the layer morphology and resistivity. For temperatures higher than 450°C, some thermal grooving assisted by the crystal defects (cross hatch) occurred and 3D Ge layers were obtained. Finally, GeOI substrates thickened with the best growth condition were evaluated by Pseudo MOSFET technique. An exceptional high hole mobility, beyond 400 cm2/V.s was observed