Nitride-Lined Isolation Cavity Mitigates Regrowth in Semiconductor Devices
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Limiting regrowth and threshold voltage (Vt) shift is a significant challenge in gate first, metal gate, high k field effect transistor (FET) production, particularly when using HfO2 gate dielectrics, as it leads to deleterious effects such as thinner inversion thickness and increased regrowth prevalence compared to HfSiON-based processing techniques.
Innovation Solution
A semiconductor device and method involving a substrate with a nitride-lined isolation cavity partially filled with a hafnium-containing dielectric, which mitigates regrowth and Vt shift by using HfSiON in shallow trench isolation (STI) fill processing, reducing oxygen diffusion from SiO2.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If HfO2 gate dielectrics are used, then thinner inversion thickness can be achieved, but regrowth and Vt shift occurrence increases
Solution Approach 1:
A nitride liner is introduced as an intermediary layer between the SiO2 fill material and the semiconductor device structures. This nitride liner acts as a diffusion barrier that prevents oxygen from the SiO2 from diffusing into the device, thereby preventing regrowth and Vt shift while allowing the use of HfO2 gate dielectrics for achieving thinner inversion thickness
Solution Approach 2:
The isolation structure uses a composite material approach by combining nitride liner with SiO2 fill material. This composite structure leverages the diffusion barrier properties of nitride while utilizing the fill capabilities of SiO2, resolving the contradiction between achieving thin inversion thickness and preventing regrowth effects
2Ease of manufacture
If SiO2 is used for STI fill, then ease of manufacture is improved, but oxygen diffusion causing regrowth and Vt shift worsens
Solution Approach 1:
The nitride liner serves as an intermediary barrier layer that blocks oxygen diffusion from the SiO2 fill material into the semiconductor devices. This allows the continued use of SiO2 for STI fill (maintaining ease of manufacture) while preventing the harmful oxygen diffusion that causes regrowth and Vt shift
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
The approach effectively reduces regrowth and Vt shift effects by incorporating HfSiON into STI trench fill, enhancing the scalability and performance of semiconductor devices by maintaining thinner inversion thickness and minimizing parasitic device capacitance.
Implementation Method 1
nitride lining the cavity... effectively reduces regrowth and Vt shift effects by incorporating HfSiON into STI trench fill, enhancing the scalability and performance of semiconductor devices by maintaining thinner inversion thickness and minimizing parasitic device capacitance
Data Source
AI summary
A semiconductor device includes a substrate having at least one nitride material lined isolation cavity; and a hafnium containing dielectric fill at least partially contained in and at least partially covering at least a portion of the at least one nitride lined isolation cavity.