Semiconductor device and manufacturing method thereof
A semiconductor device comprise a substrate, source/drain regions, a channel region, a gate dielectric layer and a gate conductive layer, wherein the gate dielectric layer comprises a barrier layer, a storage layer, a first interface layer, a tunneling layer, a second interface layer. In accordance with the semiconductor device and the manufacturing method of the present invention, an interface layer is added between the storage layer and tunneling layer in the gate dielectric by adjusting process step, and the peak concentration and peak location of nitrogen can be flexibly adjusted, effectively improving the quality of the interface between the storage layer and the tunneling layer in the gate dielectric layer, increasing process flexibility, improving device reliability and current characteristics.
1. A method of manufacturing a semiconductor device, comprising the steps of:
forming a block layer and a storage layer on side surfaces of a dummy gate structure;
performing oxidation and deposition processes, to form a first interface layer on the storage layer, wherein, the oxidation and deposition processes include at least a plurality of oxidation sub-steps and deposition sub steps alternately performed; and optionally, adjusting a concentration and time sequence of a precursor, reducing gas, and oxidizing gas, to control the oxidation sub-steps and the deposition sub-steps;
forming a continuous, single-layer tunneling layer on the first interface layer by periodically adjusting a concentration or content ratio of a gas composition containing non-oxygen elements;
performing annealing to break chemical bonds between elements on a surface of the tunneling layer so that each of the elements is re-bound in accordance with its bond energy to form a second interface layer on a surface of the tunneling layer, wherein during the annealing, a temperature is controlled over time such that the surface elements re-distribute and recombine to form silicon oxide in the second interface layer, wherein the tunneling layer is made of a high-k material and preferably nitrogen oxide; and optionally, the first interface layer and/or the second interface layer is made of oxide; and
forming a channel of polycrystalline material on the second interface layer, wherein, the step of forming the channel of polycrystalline material further comprises forming an amorphous material layer on the second interface layer and performing a second annealing to convert the amorphous material layer into the channel of poly crystalline material.
2. The method according to claim 1 , wherein the block layer includes at least one of a single-layer structure or a multi-layer stacked structure of materials selected from silicon oxide, aluminum oxide, hafnium oxide, or a combination thereof; and optionally, the storage layer is a single layer structure or a multi-layer stacked structure of materials selected from SiN, HfOx, ZrOx, YOx or a combination thereof.
3. The method according to claim 1 , which includes during the step of forming the tunneling layer, changing the concentration or the content ratio of a gas component of the gas composition to adjust the content ratio between the non-oxygen elements.
4. The method according to claim 1 , wherein the tunneling layer is formed to have a thickness between 2 to 8 nanometers and the second interface layer is formed to have a thickness of 1 nanometer.
5. The method according to claim 1 , which includes during the step of forming the tunneling layer, adjusting at least one of a peak concentration or peak location of nitrogen.