Semiconductor structures and methods of forming them

Abstract

A semiconductor structure and its forming method, the forming method comprising: providing a substrate and fins protruding from the substrate, the material of the fins contains germanium, the substrate has an isolation layer covering the side walls of the fins, and isolating The top of the layer is lower than the top of the fin; an atomic layer deposition process is used to form a dummy gate oxide layer on the top and side walls of the fin exposed by the isolation layer, and the process temperature of the atomic layer deposition process is the first temperature; a dummy gate oxide layer across the fin is formed. Gate, the dummy gate covers the surface of the dummy gate oxide layer; a dielectric layer is formed on the isolation layer, the dielectric layer covers the sidewall of the dummy gate and exposes the top of the dummy gate; removes the dummy gate and dummy gate oxide layer, exposing the top of the fin and part of the sidewall ; Forming an interface layer on the exposed top and sidewall of the fin, the process temperature for forming the interface layer is a second temperature, and the second temperature is less than or equal to the first temperature. The invention can prevent the germanium element in the fin from diffusing into the interface layer, thereby improving the interface characteristics between the interface layer and the fin, and enhancing carrier mobility.

Description

technical field

[0001] The invention relates to the technical field of semiconductor manufacturing, in particular to a semiconductor structure and a forming method thereof. Background technique

[0002] Carrier mobility is a measure of the overall movement of electrons and holes within a semiconductor structure. The carrier mobility has an important influence on the electrical properties of the semiconductor structure: on the one hand, the carrier mobility determines the conductivity of the semiconductor material, the greater the carrier mobility, the greater the conductivity, so when the same current passes through , the smaller the power consumption. On the other hand, the carrier mobility affects the operating frequency of the semiconductor structure. The greater the carrier mobility, the shorter the time for carriers to cross the base region, so the frequency response characteristics of the semiconductor structure are more excellent.

[0003] Studies have found that co...

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