Laser Crystallized Silicon Film Defect Reduction
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Solution Overview
Problem
Conventional methods for forming single-crystal silicon thin films using laser-induced epitaxial growth often result in ablation defects due to protrusions on the surface, leading to uneven film thickness and reduced yield in semiconductor device manufacturing.
Innovation Solution
A method involving the formation of a seed layer on a substrate, followed by the deposition of an amorphous silicon layer doped with impurities, which is then subjected to a laser beam-induced phase change to transform into a single-crystal silicon layer, utilizing selective epitaxial growth and ion implantation to control the crystallization process and minimize defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If laser beam is irradiated onto amorphous silicon thin film to induce phase change, then single-crystal silicon thin film is formed, but protrusions are formed on surface causing ablation defects and uneven thickness
Solution Approach 1:
The patent applies preliminary action by doping the amorphous silicon layer with impurities (such as phosphorus or boron) at a concentration of 1×10^19 to 1×10^21 atoms/cm³ before laser irradiation. This pre-doping modifies the material properties to control the phase change process, preventing protrusion formation and ablation defects during laser-induced crystallization, thereby achieving uniform film thickness and high yield
2Reliability
If conventional LEG method is used to form single-crystal silicon, then crystallization is achieved, but ablation defects occur reducing productivity
Solution Approach 1:
The patent applies parameter changes by modifying the impurity concentration in the amorphous silicon layer to a specific range (1×10^19 to 1×10^21 atoms/cm³) before laser irradiation. This parameter modification changes the thermal and electrical properties of the material, enabling controlled phase change that prevents ablation defects while maintaining high crystallization quality, thus improving both reliability and productivity
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 significantly reduces ablation defects, achieves a more uniform thickness, and enhances the planarity of the single-crystal silicon layer, thereby improving manufacturing yield and productivity.
Implementation Method 1
A laser beam is irradiated onto the amorphous silicon layer to produce a phase change of the amorphous silicon layer and change the amorphous silicon layer into a single-crystal silicon layer
Implementation Method 2
The laser beam is projected onto the amorphous silicon thin film to heat the amorphous silicon thin film and change the amorphous silicon thin film into a single-crystal silicon thin film through a phase change. This may be referred to as laser induced epitaxial growth (LEG)
Implementation Method 3
doping the amorphous silicon layer with an impurity includes doping the amorphous silicon layer through an ion implantation on an upper face of the amorphous silicon layer
Data Source
AI summary
Methods for manufacturing a semiconductor device include forming a seed layer containing a silicon material on a substrate. An amorphous silicon layer containing amorphous silicon material is formed on the seed layer. The amorphous silicon layer is doped with an impurity. A laser beam is irradiated onto the amorphous silicon layer to produce a phase change of the amorphous silicon layer and change the amorphous silicon layer into a single-crystal silicon layer based on the seed layer.