Poly-Silicon Doping Region Lateral Diffusion Control
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Solution Overview
Problem
Current methods for forming doping regions in silicon-containing layers are prone to lateral diffusion, leading to uncontrollable area expansion and reduced device performance as device sizes shrink.
Innovation Solution
A method involving the formation of a substrate with a poly-silicon layer, followed by the deposition of an ultra-thin silicon oxide layer, and subsequent doping regions formed under this oxide layer to suppress lateral diffusion through 'vacancy diffusion' and reduce interstitial diffusion, thereby maintaining precise control over the doping region.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional doping methods are used in silicon-containing layers, then doping regions can be formed, but lateral diffusion occurs causing the doping region area to become greater than expected
Solution Approach 1:
An ultra-thin silicon oxide layer (5-20 nm) is introduced as an intermediary barrier between the dopant source and the silicon-containing layer. This oxide layer selectively blocks interstitial diffusion pathways while allowing vacancy diffusion, thereby preventing lateral diffusion and maintaining precise doping region area control
Solution Approach 2:
The invention changes the diffusion mechanism parameter by utilizing vacancy diffusion instead of interstitial diffusion. By controlling the silicon oxide layer thickness and doping conditions, the diffusion pathway is transformed from the harmful interstitial route to the controlled vacancy route, achieving precise doping region definition
2Productivity
If device size is reduced to improve integration, then more devices can be packed, but lateral diffusion becomes more significant and worsens device performance
Solution Approach 1:
The ultra-thin silicon oxide layer serves as a mediator that enables continued scaling of device dimensions while preventing the exacerbation of lateral diffusion. This allows higher integration density to be achieved without sacrificing device performance, as the oxide layer maintains sharp doping region boundaries even in smaller devices
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 approach effectively minimizes lateral diffusion, enhancing the performance of semiconductor devices by maintaining the intended size and conductivity of the doping regions.
Implementation Method 1
suppress lateral diffusion through 'vacancy diffusion' and reduce interstitial diffusion
Implementation Method 2
suppress lateral diffusion through 'vacancy diffusion' and reduce interstitial diffusion
Implementation Method 3
An implant process is performed to form a doping region in the poly-silicon layer
Data Source
AI summary
The present invention provides a method of forming a doping region. A substrate is provided, and a poly-silicon layer is formed on the substrate. A silicon oxide layer is formed on the poly-silicon layer. An implant process is performed to form a doping region in the poly-silicon layer. The present invention further provides a method for forming a MOS.