Metal Carbide Gate Stack for Integrated Circuit Threshold Voltage Control
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Solution Overview
Problem
As integrated circuit and semiconductor devices become smaller and more highly integrated, they face challenges with electrical resistance and increased effective work function, making it difficult to manufacture devices with a required threshold voltage.
Innovation Solution
The integration of a semiconductor substrate with a device isolation layer, nanosheets, a gate stack comprising metal carbide layers with varying carbon concentrations, and impurity regions to achieve a compact size and desired effective work function, enhancing device reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If device size is reduced for higher integration, then integration density is improved, but electrical resistance increases and effective work function increases
Solution Approach 1:
The patent changes the chemical composition parameters of the gate electrode by incorporating metal carbide layers with specific carbon concentrations. This modifies the electrical properties (work function and resistance) of the gate structure to compensate for the effects of device scaling, thereby maintaining reliable electrical performance in highly integrated devices
Solution Approach 2:
The gate electrode is constructed as a composite structure comprising multiple metal carbide layers with different carbon concentrations. This composite material approach allows simultaneous optimization of electrical resistance and effective work function, resolving the contradiction between high integration density and electrical reliability
2Productivity
If device size is reduced for higher integration, then integration density is improved, but threshold voltage control becomes difficult
Solution Approach 1:
By adjusting the carbon concentration in the metal carbide gate electrode layers, the patent precisely controls the effective work function, which in turn enables accurate threshold voltage control. This parameter adjustment mechanism allows manufacturers to achieve desired electrical characteristics even in highly integrated compact devices
3Device complexity
If single-layer gate structure is used, then device structure is simple, but effective work function control is insufficient
Solution Approach 1:
The gate electrode employs local quality variation by creating layers with different carbon concentrations at different positions. This allows different regions of the gate structure to contribute differently to the overall effective work function, enabling precise control that cannot be achieved with a uniform single-layer structure
Solution Approach 2:
The multi-layer metal carbide structure with varying carbon concentrations functions as a composite material system. This composite approach provides superior effective work function control compared to simple single-layer structures, while the layers are arranged to maintain manufacturing feasibility
Data Source
AI summary
Provided are an integrated circuit device and a method of manufacturing the same. The integrated circuit device includes: a semiconductor substrate; a device isolation layer defining an active region of the semiconductor substrate; a gate insulating layer on the active region; a gate stack on the gate insulating layer; a spacer on a sidewall of the gate stack; and an impurity region provided on both sides of the gate stack, wherein the gate stack includes a metal carbide layer and a metal layer on the metal carbide layer, wherein the metal carbide layer includes a layer having a carbon content of about 0.01 at % to about 15 at %.