Abstract: A device includes a fin extending from a substrate, a gate stack over and along sidewalls of the fin, a gate spacer along a sidewall of the gate stack, and an epitaxial source/drain region in the fin and adjacent the gate spacer. The epitaxial source/drain region includes a first epitaxial layer on the fin, the first epitaxial layer including silicon, germanium, and arsenic, and a second epitaxial layer on the first epitaxial layer, the second epitaxial layer including silicon and phosphorus, the first epitaxial layer separating the second epitaxial layer from the fin. The epitaxial source/drain region further includes a third epitaxial layer on the second epitaxial layer, the third epitaxial layer including silicon, germanium, and phosphorus.

Abstract: A method for the ex vivo cultivation of oral mucosal epithelial progenitor cells and oral mucosal epithelial cells includes: subjecting an oral mucosal tissue to an enzymatic digestion treatment with collagenase, so as to obtain cell aggregates which include oral mucosal epithelial progenitor cells and oral mucosal epithelial cells; cultivating the cell aggregates with an amniotic membrane in a serum-free platelet lysate-containing medium in the absence of feeder cells, so that the cell aggregates are adhered onto the amniotic membrane; and subsequently cultivating the cell aggregates adhered on the amniotic membrane in a serum-free proliferation-facilitating medium in the absence of feeder cells.

Abstract: A method for the ex vivo cultivation of oral mucosal epithelial progenitor cells and oral mucosal epithelial cells includes: subjecting an oral mucosal tissue to an enzymatic digestion treatment with collagenase, so as to obtain cell aggregates which include oral mucosal epithelial progenitor cells and oral mucosal epithelial cells; cultivating the cell aggregates with an amniotic membrane in a serum-free platelet lysate-containing medium in the absence of feeder cells, so that the cell aggregates are adhered onto the amniotic membrane; and subsequently cultivating the cell aggregates adhered on the amniotic membrane in a serum-free proliferation-facilitating medium in the absence of feeder cells.