Thin Film Transistor Shield for Ion Implantation Doping
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Solution Overview
Problem
Conventional methods of manufacturing thin film transistors are complicated, difficult to control, and result in high rejection rates due to the need for multiple patterning processes and doping steps.
Innovation Solution
A method that forms a semiconductor layer, a gate electrode, and defines source and drain regions, using a shield for ion implantation to create doped regions without additional masks, incorporating perpendicular and inclined ion implantations to simplify the process and reduce the number of patterning steps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional doping methods with multiple masks are used, then doping precision can be achieved, but device complexity and manufacturing time increase significantly
Solution Approach 1:
The patent combines multiple doping operations into a single ion implantation process by using a carefully designed shield structure. The shield simultaneously defines multiple doped regions (source, drain, and extension regions) that would traditionally require separate masking steps, thereby reducing process complexity while maintaining doping precision
Solution Approach 2:
The patent introduces a vertical dimension by forming a three-dimensional shield structure with specific height and width dimensions. This 3D shield configuration enables selective doping in multiple horizontal regions through a single top-down ion implantation process, transforming a multi-step 2D masking problem into a single 3D shielding solution
2Manufacturing precision
If multiple patterning processes are used, then doping regions can be precisely formed, but manufacturing time and production cost increase
Solution Approach 1:
The patent performs preliminary action by pre-forming the shield structure with precise dimensions before the ion implantation step. The shield is designed in advance to have specific width and height parameters that predeterminedly define the doping regions, eliminating the need for sequential patterning operations and reducing manufacturing time
Solution Approach 2:
The shield structure serves multiple functions simultaneously: it acts as a mask for ion implantation, defines source and drain regions, creates extension regions, and protects the gate electrode. This multi-functionality consolidates what would traditionally require multiple separate patterning processes into a single operational step
3Reliability
If conventional doping methods are used, then doped regions can be formed, but parameter control difficulty and rejection rate increase
Solution Approach 1:
The patent controls doping parameters by precisely adjusting the shield's physical dimensions (width w1, height h1) and the ion implantation conditions (energy, angle). By changing these parameters, the doping concentration and distribution can be precisely controlled in a single step, improving parameter control and reducing rejection rates compared to multiple doping steps
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 method simplifies the manufacturing process, reduces time and cost, and improves product yield by eliminating the need for multiple masks and enhancing control over doping parameters.
Implementation Method 1
performing ion implantation to the semiconductor layer by using the shield as a mask, so as to form a first doped region in the first source portion and in the first drain portion
Data Source
AI summary
A method of manufacturing a thin film transistor includes forming a semiconductor layer on a base substrate; forming a gate electrode on the semiconductor layer; forming a shield on the gate electrode, wherein a perpendicular projection of the shield onto the base substrate covers a first source portion of the source region and a first drain portion of the drain region; and performing ion implantation to the semiconductor layer by using the shield as a mask, so as to form a first doped region in the first source portion and in the first drain portion, and to form a second doped region in a second source portion of the source region that is not covered by the perpendicular projection of the shield and in a second drain portion of the drain region that is not covered by the perpendicular projection of the shield.