Word Line Plug Structure for Lower GIDL in Buried Channel ICs
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Solution Overview
Problem
As integration density of IC devices with buried channel array transistors increases, the pitch between word lines decreases, leading to an increase in gate-induced drain leakage (GIDL) current, which adversely affects refresh characteristics and threshold voltage control.
Innovation Solution
The integration of a word line with a work-function control conductive plug made of conductive metal nitride, including a metal dopant, and an insulating capping pattern, which reduces resistance and improves electrical characteristics by precisely controlling the threshold voltage and reducing GIDL current.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the pitch between word lines is decreased to increase integration density, then the integration density is improved, but the gate-induced drain leakage (GIDL) current increases
Solution Approach 1:
The patent applies local quality by creating a dual-structure work function control conductive plug where only a portion (the first portion) directly contacts the gate dielectric film, while the second portion is positioned away from it. This localized configuration allows precise control of the electric field interaction at the critical interface region, reducing GIDL current generation at the word line-gate dielectric interface while maintaining the reduced pitch for high integration density.
Solution Approach 2:
The work function control conductive plug is segmented into two distinct portions: a first portion that contacts the gate dielectric film and a second portion that is positioned away from it. This segmentation enables differential control of electric field distribution - the first portion manages threshold voltage control at the interface, while the second portion extends the work function control without directly interacting with the gate dielectric, thereby suppressing GIDL current in the high-density configuration.
2Reliability
If a work function control conductive plug is added to control threshold voltage and reduce GIDL current, then the electrical characteristics are improved, but the device complexity increases
Solution Approach 1:
The patent merges multiple functions into the work function control conductive plug structure. The same conductive plug serves both as a threshold voltage control element (through its work function properties) and as a GIDL current suppression element (through its segmented configuration that manages electric field distribution). This consolidation achieves improved electrical characteristics without proportionally increasing device complexity, as the dual functionality is embedded in a single integrated structure rather than requiring separate components.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration effectively reduces GIDL current and enhances refresh characteristics by lowering the work function of the word line, thereby improving the stability and efficiency of the IC device's electrical performance.
Implementation Method 1
the word line comprises a work-function control conductive plug that comprises a conductive metal nitride comprising a metal dopant
Data Source
Figure 1
Figure 2A
Figure 2B
AI summary
Integrated circuit devices (100) may include a substrate (102) including a word line trench (WT) extending longitudinally in a first horizontal direction (X), a gate dielectric film (120) extending along an inner surface of the word line trench, a word line (WL) in a lower portion of the word line trench on the gate dielectric film and extending longitudinally in the first horizontal direction, and an insulating capping pattern (128) in an upper portion of the word line trench on the word line and extending longitudinally in the first horizontal direction. The word line may include a work-function control conductive plug (122B) including a conductive metal nitride that include a metal dopant, and the work-function control conductive plug includes a top surface in contact with a bottom surface of the insulating capping pattern, a sidewall in contact with the gate dielectric film, and a bottom surface in contact with a monolithic layer (122A).