Method for manufacturing gate stack structure in insta-metal-oxide-semiconductor field-effect-transistor

摘要

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 between germanium and the gate dielectric.

主权项

1. A method for manufacturing an insta-metal-oxide-semiconductor (i-MOS) gate stack structure, comprising the following steps of:
step 1: forming a silicon nitride layer over a silicon substrate; step 2: forming a nanopillar structure on the silicon nitride layer, the nanopillar structure comprising a silicon-germanium alloy layer in contact with the silicon nitride layer; and step 3: performing a thermal oxidation process on the nanopillar structure to cause germanium atoms in the silicon-gennanium alloy layer to penetrate underneath the 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 located between the silicon-germanium shell layer and the germanium nanosphere by oxidizing silicon atoms which are released from the silicon nitride layer or from the silicon substrate, so as to form a germanium/silicon dioxide/silicon-germanium i-MOS gate stack structure.