Selective Monolayer Doping for Semiconductor Lattice Integrity
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Solution Overview
Problem
Traditional doping processes for semiconductor materials are time-consuming and increase production costs, especially as semiconductor structures shrink, requiring higher masking resolutions and specialized equipment to control doping areas effectively.
Innovation Solution
The selective monolayer doping (SMLD) process, which involves depositing a dopant concentration on a material layer using a gas mixture, varying exposure duration and concentration, and annealing to diffuse dopants into the layer, allowing for conformal doping without damaging the crystal lattice and enabling high dopant concentrations in a single semiconductor processing chamber.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional doping processes are used with masking to control doping areas, then doping area control is achieved, but production time increases and costs increase
Solution Approach 1:
The patent extracts the masking step from the traditional doping process by using selective surface preparation (oxidation or nitridation) to create chemically distinct regions. The dopant precursor selectively deposits only on non-oxidized/non-nitrided regions, eliminating the need for physical masks and their associated alignment and removal steps, thereby reducing production time while maintaining doping area control.
Solution Approach 2:
The patent introduces an intermediary chemical layer (oxide or nitride) on the semiconductor surface that acts as a selective barrier. This intermediary layer prevents dopant deposition on specific regions without requiring physical masks, enabling area-selective doping through chemical rather than mechanical means, thus improving productivity.
2Manufacturing precision
If masking is used to control doping areas in shrinking semiconductor structures, then doping precision is maintained, but equipment complexity and cost increase
Solution Approach 1:
The patent replaces the mechanical masking system (physical masks, alignment equipment, mask writers) with a chemical selection system. Surface oxidation or nitridation creates chemically distinct regions that selectively interact with dopant precursors, eliminating the need for complex mechanical masking equipment and reducing device complexity while maintaining doping precision.
Solution Approach 2:
The patent changes the physical-chemical parameters of the semiconductor surface (oxidation state, nitridation level) to create selective deposition regions. By controlling surface chemistry rather than physical mask geometry, the process achieves precise doping area control without requiring specialized masking equipment, thereby reducing equipment complexity.
3Reliability
If dopant concentration is increased to maintain electrical properties in smaller structures, then electrical performance is maintained, but crystal lattice damage increases
Solution Approach 1:
The patent performs preliminary surface preparation (oxidation or nitridation) before dopant deposition to create a controlled surface chemistry. This preliminary action enables selective dopant incorporation at high concentrations only in desired regions, allowing high dopant doses without the need for high-energy implantation that would damage the crystal lattice, thus maintaining both electrical performance and lattice integrity.
Solution Approach 2:
The patent replaces high-energy ion implantation (mechanical/physical process causing lattice damage) with a chemical vapor deposition process. The dopant precursor decomposes and deposits as atoms or molecules that can be incorporated into the lattice at lower energies, achieving high dopant concentrations without the crystal lattice damage associated with traditional high-dose ion implantation.
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 process achieves high dopant concentrations while maintaining the integrity of the crystal lattice, allowing for continued shrinkage of semiconductor structures and reducing production costs by enabling precise control over dopant distribution without altering dielectric areas, improving yield and efficiency.
Implementation Method 1
exposing the doped semiconductor feature to a gas mixture containing a dopant to selectively deposit the concentration of dopant on the material layer
Implementation Method 2
annealing the concentration of dopant to diffuse the concentration of dopant into the material layer
Data Source
AI summary
Methods and apparatus for forming doped material layers in semiconductor devices using an integrated selective monolayer doping (SMLD) process. A concentration of dopant is deposited on a material layer using the SMLD process and the concentration of dopant is then annealed to diffuse the concentration of dopant into the material layer. The SMLD process conforms the concentration of dopant to a surface of the material layer and may be performed in a single CVD chamber. The SMLD process may also be repeated to further alter the diffusion parameters of the dopant into the material layer. The SMLD process is compatible with p-type dopant species and n-type dopant species.