Heavy Halogenide Ion Implantation Profile Control
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Solution Overview
Problem
Plasma doping systems face challenges in achieving precise control of ion implant profiles and suffer from co-implantation of undesirable ionic species, leading to reduced dopant ion incorporation and formation of defects in substrates due to the presence of unwanted ions like H, He, and F, which are difficult to monitor and eliminate.
Innovation Solution
Incorporating heavy halogenated compounds like BI3 as dopant gas feedstock to maximize desired dopant ions, control depth and doping profiles, and balance etching and deposition, while using specific plasma doping parameters to minimize the impact of undesirable species, such as adjusting ion energies to confine iodine substitute species to surface layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If plasma doping systems are used to dope substrates, then doping requirements of state-of-the-art electronic devices can be met, but co-implantation of undesirable ionic species (H, He, F) occurs leading to reduced dopant ion incorporation and formation of defects
Solution Approach 1:
The patent changes the chemical composition parameters of the dopant gas feedstock by incorporating heavy halogenated compounds (BI3, PBr3, AsI3) with specific molecular weights and bond strengths. This parameter change modifies the plasma chemistry to reduce co-implantation of undesirable ions while maintaining precise dopant profile control through adjusted ion energies and gas flow rates
Solution Approach 2:
The patent introduces heavy halogen atoms (I, Br) as intermediary species in the plasma that act as mass filters. These intermediaries preferentially carry dopant ions to the substrate while their high mass reduces the transmission of lighter undesirable ions (H, He, F), thereby mediating the implantation process to eliminate harmful co-implantation
2Manufacturing precision
If conventional dopant gases are used, then doping process can be performed, but precise control of ion implant profiles and depth is difficult to achieve
Solution Approach 1:
The patent changes physical parameters of the dopant gas by selecting heavy halogenated compounds with specific molecular weights and vapor pressures. These parameter changes enable precise control of ion implant profiles through adjusted ion energies and gas flow rates, simplifying the overall process control while achieving the desired doping precision
3Reliability
If heavy halogenated compounds are used as dopant gas feedstock, then fraction of desired dopant ions is significantly increased and co-implantation of unwanted species is reduced, but process parameters must be precisely optimized
Solution Approach 1:
The patent optimizes process parameters including ion energy, gas flow rate, and plasma power based on the specific properties of heavy halogenated compounds. These parameter changes maximize dopant ion incorporation efficiency while the inherent mass filtering effect of heavy halogens reduces co-implantation, achieving high reliability with manageable process 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 significantly increases the fraction of desired dopant ions, reduces co-implantation of unwanted species, and allows for precise control of dopant profiles, enhancing the quality of ion implantation and reducing residual defects, enabling the formation of ultra-short junctions with improved device performance.
Implementation Method 1
The electric field within the plasma sheath accelerates ions toward the substrate, thereby implanting the ions into the surface of the substrate
Implementation Method 2
beam-line and cluster beam ion implantation systems accelerate ions with an electric field and then select ions with the desired mass-to-charge ratio. The selected ions are then implanted into the substrate
Implementation Method 3
The negative bias on the substrate repels electrons from the surface of the substrate, thereby creating a sheath of positive ions
Implementation Method 4
Incorporating heavy halogenated compounds like BI3 as dopant gas feedstock to maximize desired dopant ions, control depth and doping profiles, and balance etching and deposition, while using specific plasma doping parameters to minimize the impact of undesirable species, such as adjusting ion energies to confine iodine substitute species to surface layers
Data Source
AI summary
A method of plasma doping includes providing a dopant gas comprising a dopant heavy halogenide compound gas to a plasma chamber. A plasma is formed in the plasma chamber with the dopant heavy halogenide compound gas and generates desired dopant ions and heavy fragments of precursor dopant molecule. A substrate in the plasma chamber is biased so that the desired dopant ions impact the substrate with a desired ion energy, thereby implanting the desired dopant ions and the heavy fragments of precursor dopant molecule into the substrate, wherein at least one of the ion energy and composition of the dopant heavy halogenide compound is chosen so that the implant profile in the substrate is substantially determined by the desired dopant ions.