Abstract: A semiconductor device includes a gate structure on a substrate, in which the gate structure includes a main branch extending along a first direction on the substrate and a sub-branch extending along a second direction adjacent to the main branch. The semiconductor device also includes a first doped region overlapping the main branch and the sub-branch according to a top view and a second doped region overlapping the first doped region.

Abstract: A method for manufacturing a metal-oxide-semiconductor (MOS) gate stack structure in an insta-MOS field-effect-transistor (i-MOSFET) includes the following steps of: forming a silicon nitride layer over a silicon substrate; forming a nanopillar structure including a silicon-germanium alloy layer in contact with the silicon nitride layer; and performing a thermal oxidation process on the nanopillar structure to cause germanium atoms in the silicon-germanium alloy layer to penetrate the underneath silicon nitride layer to form a silicon-germanium shell layer in contact with the silicon substrate and a germanium nanosphere located over the silicon germanium shell layer, and to form a separating layer between the silicon-germanium shell layer and the germanium nanosphere by oxidizing silicon atoms from the silicon nitride layer or the silicon substrate, thereby forming a germanium/silicon dioxide/silicon-germanium i-MOS gate stack structure capable of solving interfacial issues between silicon and germanium and b

Abstract: A method for manufacturing a metal-oxide-semiconductor (MOS) gate stack structure in an insta-MOS field-effect-transistor (i-MOSFET) includes the following steps of: forming a silicon nitride layer over a silicon substrate; forming a nanopillar structure including a silicon-germanium alloy layer in contact with the silicon nitride layer; and performing a thermal oxidation process on the nanopillar structure to cause germanium atoms in the silicon-germanium alloy layer to penetrate the underneath silicon nitride layer to form a silicon-germanium shell layer in contact with the silicon substrate and a germanium nanosphere located over the silicon germanium shell layer, and to form a separating layer between the silicon-germanium shell layer and the germanium nanosphere by oxidizing silicon atoms from the silicon nitride layer or the silicon substrate, thereby forming a germanium/silicon dioxide/silicon-germanium i-MOS gate stack structure capable of solving interfacial issues between silicon and germanium and b