Uniform Misfit Dislocations in Strained Silicon on SiGe
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional methods for forming a relaxed SiGe layer require thick multi-layered buffer layers, increasing manufacturing time and cost, and result in non-uniform misfit dislocations leading to variable device performance and defects.
Innovation Solution
A method involving ion-implantation of atoms to form uniformly distributed interstitial dislocation loops in a compressively strained SiGe layer, followed by annealing to create uniformly distributed misfit dislocations, allowing for the formation of a relaxed SiGe layer without the need for thick buffer layers, enabling controlled stress distribution and improved device performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a thick multi-layered SiGe buffer layer is used to achieve misfit dislocations, then the SiGe layer can be relaxed, but the manufacturing time and cost significantly increase
Solution Approach 1:
The invention changes the key parameter from buffer layer thickness to ion implantation dose and energy. By controlling ion implantation parameters (dose, energy, species), misfit dislocations are generated at controlled densities without requiring thick buffer layers, thus reducing manufacturing time while achieving the desired relaxed SiGe structure
Solution Approach 2:
The invention replaces the mechanical approach (building thick buffer layers to generate dislocations) with a radiation-based approach (ion implantation). The ion implantation process directly introduces interstitial atoms that nucleate dislocation loops, substituting the mechanical accumulation of layers with a controlled radiation damage process
2Reliability
If a thick multi-layered SiGe buffer layer is used to achieve misfit dislocations, then the SiGe layer can be relaxed, but the manufacturing cost significantly increases
Solution Approach 1:
The invention changes the key parameter from buffer layer thickness to ion implantation dose and energy. By controlling ion implantation parameters (dose, energy, species), misfit dislocations are generated at controlled densities without requiring thick buffer layers, thus reducing manufacturing time while achieving the desired relaxed SiGe structure
Solution Approach 2:
The invention replaces the mechanical approach (building thick buffer layers to generate dislocations) with a radiation-based approach (ion implantation). The ion implantation process directly introduces interstitial atoms that nucleate dislocation loops, substituting the mechanical accumulation of layers with a controlled radiation damage process
3Reliability
If conventional SiGe buffer layer approach is used, then misfit dislocations can be formed, but the dislocations are random and highly non-uniform
Solution Approach 1:
The invention introduces feedback control through precise ion implantation parameters. By controlling ion species, dose, energy, and temperature, the nucleation and distribution of dislocation loops are controlled, ensuring uniform misfit dislocation densities across the layer. This feedback-based control replaces the random heterogeneous nucleation of conventional methods
Solution Approach 2:
The invention changes the key parameter from buffer layer thickness to ion implantation dose and energy. By controlling ion implantation parameters (dose, energy, species), misfit dislocations are generated at controlled densities without requiring thick buffer layers, thus reducing manufacturing time while achieving the desired relaxed SiGe structure
4Reliability
If a thick SiGe buffer layer is used, then relaxation can be achieved, but it cannot be easily applied to silicon-on-insulator (SOI)
Solution Approach 1:
The invention changes the key parameter from buffer layer thickness to ion implantation dose and energy. By controlling ion implantation parameters (dose, energy, species), misfit dislocations are generated at controlled densities without requiring thick buffer layers, thus reducing manufacturing time while achieving the desired relaxed SiGe structure
Solution Approach 2:
The invention transitions from a thickness-based approach (vertical dimension) to a radiation-dose-based approach (energy dimension). This dimensional change allows the process to be applied to thin SOI structures where thick buffer layers would be incompatible, enabling the technique to work within the thickness constraints of SOI technology
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 allows for the efficient production of a relaxed SiGe layer with uniform misfit dislocations, enhancing device performance by applying consistent biaxial tensile strain to the silicon layer, thus improving transistor performance without the drawbacks of thick buffer layers.
Implementation Method 1
Atoms are ion-implanted to form uniformly distributed interstitial dislocation loops in the SiGe layer
Implementation Method 2
Annealing is performed to form uniformly distributed misfit dislocations at the SiGe-silicon interface
Data Source
AI summary
A method for forming a semiconductor substrate structure is provided. A compressively strained SiGe layer is formed on a silicon substrate. Atoms are ion-implanted onto the SiGe layer to cause end-of-range damage. Annealing is performed to relax the strained SiGe layer. During the annealing, interstitial dislocation loops are formed as uniformly distributed in the SiGe layer. The interstitial dislocation loops provide a basis for nucleation of misfit dislocations between the SiGe layer and the silicon substrate. Since the interstitial dislocation loops are distributed uniformly, the misfit locations are also distributed uniformly, thereby relaxing the SiGe layer. A tensilely strained silicon layer is formed on the relaxed SiGe layer.