Patent ID: 11942546
Assignee: NATIONAL TAIWAN UNIVERSITY
Field: Semiconductors (Electrical engineering)
Classification: CPC H | IPC H

Claim 10:
11. A method, comprising:
forming semiconductor layers vertically stacked over a substrate;
forming a dummy gate structure over the semiconductor layers;
forming gate spacers on opposite sidewalls of the dummy gate structure;
forming inner spacers vertically between two adjacent semiconductor layers;
forming source/drain structures on opposite sides of the dummy gate structure after forming the inner spacers;
removing the dummy gate structure after forming the source/drain structures;
forming an interfacial layer in contact with each of the semiconductor layers;
forming a Hf1-xZrxO2 layer having quasi-antiferroelectric property over the interfacial layer, wherein the Hf1-xZrxO2 layer has a portion in direct contact with the gate spacers, the portion has a U-shape cross-sectional profile, and a bottom surface of the portion is higher than bottom surfaces of the gate spacers, wherein x is about 0.75, wherein a crystalline structure of the Hf1-xZrxO2 layer is a mixture of a tetragonal phase and an orthorhombic phase, and a ratio of the tetragonal phase to the orthorhombic phase in the Hf1-xZrxO2 layer is in a range from about 1:10 to about 10:1, and wherein in a polarization-voltage curve of the Hf1-xZrxO2 layer, when a sweep voltage of 3 V is applied, a remnant polarization (Pr) of the Hf1-xZrxO2 layer is in a range from about 0.5 μC/cm2 to about 5 μC/cm2, and a coercive voltage (Vc) of the Hf1-xZrxO2 layer is in a range from about 0.1 V to about 0.5 V, and forming the Hf1-xZrxO2 layer comprises:
loading the substrate to an ALD chamber;
performing a first deposition cycle by supplying H2O and a Zr-containing precursor into the ALD chamber;
performing a second deposition cycle by supplying H2O and a Hf-containing precursor into the ALD chamber;
performing a third deposition cycle by supplying H2O and a Zr-containing precursor into the ALD chamber; and

forming a gate electrode over the Hf1-xZrxO2 layer.