Conformal Boron Doping of 3D Silicon Without Implant Damage
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional ion implantation techniques for ultra-shallow silicon doping in 3D semiconductor structures face challenges such as structural damage, channel effects, and shadow effects, while plasma-enhanced ALD fails to achieve conformal deposition and introduces plasma damage.
Innovation Solution
A method involving the removal of the native oxide layer, alternating deposition of silicon and boron oxide layers, followed by aluminum oxide passivation, and laser or rapid thermal annealing to drive boron dopants into the substrate, ensuring conformal and damage-free doping.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional ion implantation is used for ultra-shallow silicon doping in 3D structures, then doping can be achieved, but structural damage, channel effects, and shadow effects occur
Solution Approach 1:
The patent replaces the mechanical ion implantation process with a chemical deposition process (ALD). Instead of physically bombarding ions into the silicon substrate, boron-containing precursors are deposited as thin films through surface reactions, eliminating mechanical damage while achieving precise dopant placement through controlled deposition thickness
Solution Approach 2:
The patent changes the fundamental parameter of the doping process from high-energy particle bombardment to low-energy chemical deposition. By controlling deposition temperature, precursor flow rates, and cycle numbers, precise dopant concentration and distribution are achieved without the harmful effects of ion implantation
2Manufacturing precision
If plasma-enhanced ALD is used to deposit B2O3 for boron doping, then doping can be achieved, but conformal deposition cannot be achieved due to shadow effect and plasma damage is introduced
Solution Approach 1:
The patent uses thermal ALD in an inert or controlled atmosphere without plasma activation. The self-limiting surface reactions of ALD proceed effectively at elevated temperatures without requiring plasma, eliminating plasma-induced damage while maintaining the conformal deposition advantage of ALD on 3D structures
Solution Approach 2:
The patent changes the activation method from plasma-enhanced to thermally-driven surface reactions. By optimizing deposition temperature and precursor parameters, the same doping function is achieved without plasma, eliminating shadow effects and plasma damage while preserving conformal coverage
3Manufacturing precision
If B2O3 is deposited through thermal ALD, then conformal deposition can be achieved, but nucleation is difficult and film formation fails at certain thickness
Solution Approach 1:
The patent introduces an intermediary oxide layer (such as SiO2 or Al2O3) deposited before the B2O3 layer. This intermediary layer provides suitable nucleation sites for B2O3 formation, enabling reliable film growth while maintaining the conformal deposition characteristics of thermal ALD
Solution Approach 2:
The patent performs preliminary deposition of an oxide layer before depositing B2O3. This preparatory step creates a surface that facilitates nucleation and ensures reliable film formation, allowing the subsequent B2O3 layer to form conformally and reliably at the desired thickness
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
Achieves conformal boron doping in 3D structures without structural damage or shadow effects, with precise control over dopant thickness and concentration, enhancing the performance of semiconductor devices.
Implementation Method 1
depositing an aluminum oxide passivation layer on a surface of the second group of stacked films away from the first group of stacked films
Implementation Method 2
boron-doping the silicon-based 3D substrate through laser annealing or rapid thermal annealing, where the laser annealing or the rapid thermal annealing drives boron dopants, which comprises boron oxide, into the silicon-based 3D substrate
Implementation Method 3
laser annealing
Implementation Method 4
rapid thermal annealing
Implementation Method 5
Atomic layer deposition (ALD) features in good conformality, good uniformity, and controllable atomic-scale thickness, because ALD process is controlled by self-limiting surface reactions
Data Source
AI summary
A method and an apparatus for conformal boron doping of a three-dimensional structure. The method comprises: removing an oxide layer from a surface of a silicon-based three-dimensional (3D) substrate; forming, after removing the oxide layer, a first group of stacked films on a surface of the silicon-based three-dimensional substrate; forming a second group of stacked films on a surface of the first group of stacked films away from the silicon-based 3D substrate; depositing an aluminum oxide passivation layer on a surface of the second group of stacked films away from the first group of stacked films; and boron-doping the silicon-based 3D substrate through laser annealing or rapid thermal annealing, where the laser annealing or the rapid thermal annealing drives boron dopants, which comprises boron oxide, into the silicon-based 3D substrate via an auxiliary layer.