FinFET Conformal Transfer Doping via Knock-On Implantation
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Solution Overview
Problem
Existing FinFET doping techniques struggle to achieve deep, uniform doping profiles without damaging the fin structures, particularly at smaller feature sizes, leading to inefficiencies and surface damage during processing.
Innovation Solution
A method involving the formation of a doped amorphous layer with a higher dopant concentration over a fin structure, followed by a knock-on implantation process that converts the amorphous layer into crystalline material, integrating it into the fin structure, thereby forming a doped feature with deeper and more uniform doping profiles without the need for subsequent wet etching or cleaning processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If existing FinFET doping techniques are used, then doping can be performed on fin structures, but the doping profiles are not deep or uniform and surface damage occurs
Solution Approach 1:
A doped amorphous layer is formed over the fin structure before the knock-on implantation process. This preliminary layer serves as a dopant source that protects the fin structure during doping, enabling deep and uniform doping profiles without surface damage to the crystalline fin structure
Solution Approach 2:
The patent changes the physical state of the dopant layer from crystalline to amorphous, and changes the doping mechanism from direct ion implantation into crystalline structure to a two-step process involving amorphous layer formation followed by knock-on implantation. This parameter change enables deeper and more uniform doping while avoiding surface damage
2Productivity
If conventional doping processes are used, then fin structures can be doped, but subsequent wet etching or cleaning processes are required which increase processing complexity
Solution Approach 1:
The doped amorphous layer serves multiple functions: it acts as a dopant source, protects the fin structure during doping, and can be selectively removed afterward. This self-service approach eliminates the need for separate wet etching or cleaning processes, reducing processing complexity and improving efficiency
Solution Approach 2:
The patent combines multiple functions into a single doped amorphous layer: dopant reservoir, protective layer, and sacrificial layer. This merging of functions reduces the total number of processing steps required compared to conventional doping approaches
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 enables the creation of FinFET devices with improved doping profiles and reduced surface damage, enhancing processing efficiency and minimizing space between fins, while maintaining the integrity of the fin structures.
Implementation Method 1
performing a knock-on implantation process to drive dopant from the doped amorphous layer into a portion of the fin structure
Implementation Method 2
the knock-on implantation process converts at least a portion of the amorphous silicon into crystalline silicon
Data Source
AI summary
Doping techniques for fin-like field effect transistors (FinFETs) are disclosed herein. An exemplary method includes forming a fin structure, forming a doped amorphous layer over a portion of the fin structure, and performing a knock-on implantation process to drive a dopant from the doped amorphous layer into the portion of the fin structure, thereby forming a doped feature. The doped amorphous layer includes a non-crystalline form of a material. In some implementations, the knock-on implantation process crystallizes at least a portion of the doped amorphous layer, such that the portion of the doped amorphous layer becomes a part of the fin structure. In some implementations, the doped amorphous layer includes amorphous silicon, and the knock-on implantation process crystallizes a portion of the doped amorphous silicon layer.