Selective N-Type Doped Material Formation via Epitaxy
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Solution Overview
Problem
Conventional methods for forming highly-doped n-type semiconductor material face challenges such as high deposition temperatures, slow and expensive cyclical deposition and etch processes, and inability to achieve low resistivity values, making it difficult to selectively form n-type semiconductor material for advanced semiconductor devices like CMOS devices.
Innovation Solution
The method involves providing a substrate with distinct areas for selective deposition of n-type doped semiconductor material using epitaxial growth techniques at lower temperatures, where the deposited material forms as monocrystalline over one area and non-monocrystalline over another, allowing for a selective etch barrier to remove the non-monocrystalline material, thereby forming regions with high dopant concentration and low contact resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If traditional deposition, pattern, and etch processes are used to form highly-doped n-type semiconductor material, then the material can be deposited, but the deposition temperature is undesirably high and low resistivity values are not achievable
Solution Approach 1:
The patent changes the deposition parameters by using a two-stage process: first depositing at a lower temperature (400-600°C) to form an initial layer, then performing a rapid thermal anneal (RTA) at high temperature (900-1100°C) for a short duration (5-30 seconds). This parameter change sequence achieves both low overall process temperature and high doping precision, resolving the contradiction between temperature control and doping quality.
Solution Approach 2:
The patent performs a preliminary low-temperature deposition to form an initial semiconductor layer before the high-temperature RTA step. This preliminary action prepares the substrate and dopant distribution in advance, allowing the subsequent rapid thermal anneal to achieve precise doping without requiring prolonged high-temperature exposure, thus resolving the temperature-precision contradiction.
2Manufacturing precision
If cyclical deposition and etch processes are used to selectively form highly-doped n-type semiconductor material, then selectivity can be achieved, but the process is relatively slow and expensive
Solution Approach 1:
The patent merges the deposition and doping steps into a single simultaneous process, where dopant is introduced during the semiconductor layer deposition. This eliminates the need for separate cyclical deposition and etch processes, achieving both selectivity and high productivity by reducing the total number of process steps.
Solution Approach 2:
The patent uses a continuous deposition process with in-situ dopant introduction, maintaining continuous useful action throughout the film formation. This eliminates the idle time and material removal steps inherent in cyclical processes, significantly improving productivity while maintaining selectivity through controlled deposition conditions.
3Productivity
If conventional device scaling techniques are used, then speed and density of integrated circuits improve, but significant challenges face future technology nodes
Solution Approach 1:
The patent applies local quality by introducing dopant selectively during deposition only in regions where n-type conductivity is required. This localized doping approach enables continued device scaling and increased circuit density without requiring complex geometric modifications, as the electrical properties are tailored locally rather than through overall structural complexity.
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 enables the formation of highly-doped n-type semiconductor material at lower temperatures and with reduced costs, achieving low contact resistance and high selectivity, suitable for forming source and drain regions of semiconductor devices like CMOS devices.
Implementation Method 1
depositing an n-type doped semiconductor material overlying the surface, wherein the n-type doped semiconductor material forms as doped monocrystalline material overlying the first area and as doped non-monocrystalline material overlying the second area
Implementation Method 2
An etch rate of the monocrystalline material overlying the first area may be much lower than an etch rate of the non-monocrystalline material overlying the second area. Thus, the monocrystalline material overlying the first area can serve as an etch barrier during a step of removing the non-monocrystalline material overlying the second area
Data Source
AI summary
A method for selectively forming an n-type doped material on a surface of a substrate is disclosed. A system for performing the method and structures and devices formed using the method are also disclosed.