Cluster Ion Implantation for High-Density Arsenic and Phosphorus Doping
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional ion implantation methods face challenges in efficiently utilizing dopant source compounds that are not in gaseous form, require specific volatilization and ionization properties, and often result in lower dopant ion density due to the use of monoatomic species, limiting the efficiency of arsenic and phosphorus implantation in semiconductor manufacturing.
Innovation Solution
The use of polyatomic dopant source compounds such as phosphorus and arsenic hydrides, halides, and oxyhalides, as well as substituted phosphanes and arsines, which can form cluster compounds and bonds, allowing for increased dopant ion density and efficient ion implantation by being volatilized, ionized, and processed into high-density ion beams for substrate implantation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If monoatomic dopant source compounds are used for ion implantation, then the ionization and separation process is simpler, but the dopant ion density per unit volume is significantly lower
Solution Approach 1:
The patent merges multiple dopant atoms into cluster ions (e.g., As4+, P4+, As3+, P3+), combining several dopant sources into single ionized entities. This allows multiple dopant atoms to be delivered simultaneously in each ion impact, dramatically increasing dopant ion density while the electrode arrays handle the clustered ions as unified charged particles, managing complexity through unified charge-based control
Solution Approach 2:
The invention uses composite dopant source compounds containing multiple dopant atoms bonded together (cluster compounds like As4, P4, As3P). These composite molecular structures serve as multi-functional dopant sources where each molecule contains multiple active dopant atoms that can be ionized and implanted together, achieving high dopant density through molecular composition rather than atomic delivery
2Quantity of substance
If polyatomic dopant source compounds are used to increase dopant ion density, then more dopant atoms can be delivered per unit volume, but the compounds must meet stringent criteria for gaseous form, transport properties, ionizability, and vacuum chamber compatibility
Solution Approach 1:
The patent systematically varies parameters of dopant source compounds including molecular structure (cluster size, bonding), physical state (gas, liquid, solid), and chemical composition to optimize performance. Specific compounds like As4, P4, As3P, and their derivatives are selected based on their vapor pressure, ionization energy, and stability characteristics, adjusting these parameters to achieve high dopant density while maintaining process compatibility
Solution Approach 2:
The invention utilizes phase transitions of dopant source compounds, particularly vaporization from liquid or solid states to gaseous form for ionization. The selected polyatomic compounds (e.g., As4 liquid, P4 solid) undergo controlled phase transitions to generate gaseous dopant precursors that can be efficiently ionized in the ion source, enabling high dopant ion density delivery through controlled phase change processes
3Productivity
If conventional monoatomic dopant sources are used, then the implantation process is simpler to control, but the efficiency and productivity of dopant delivery is limited
Solution Approach 1:
Multiple dopant atoms are merged into single cluster ion entities (As4+, P4+, As3P+), delivering multiple dopant atoms per ion impact event. This merging strategy multiplies the dopant delivery efficiency without proportionally increasing system complexity, as the ionization and acceleration processes remain fundamentally similar to conventional single-atom ion implantation
Solution Approach 2:
The patent develops a universal approach using cluster ion implantation that can deliver multiple dopant species (arsenic, phosphorus, and their combinations) through a single implantation system. The same ion source and acceleration infrastructure handles various cluster compositions, providing multi-functional dopant delivery capability while maintaining controlled process complexity through standardized equipment operation
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 enhances the efficiency of ion implantation by increasing the number of dopant ions per unit volume, improving the quality and quantity of arsenic and phosphorus ions implanted in substrates, particularly in semiconductor devices, through the use of polyatomic compounds that can form cluster ions and bonds, thereby addressing the limitations of monoatomic species.
Implementation Method 1
The source compound, if not in the gas phase, may be volatilized by sublimation or vaporization techniques from solid form or liquid form source compounds
Implementation Method 2
The resulting dopant gas then is subjected to ionization to form ionic species that are separated by electrode arrays to form an ion beam
Implementation Method 3
Ions in the ion beam are accelerated through a beamline structure and impinged on a substrate to effect implantation of the ions in the substrate
Implementation Method 4
Ions in the ion beam are accelerated through a beamline structure and impinged on a substrate to effect implantation of the ions in the substrate
Data Source
AI summary
An ion implantation method, in which a dopant source composition is ionized to form dopant ions, and the dopant ions are implanted in a substrate. The dopant source composition includes cluster phosphorus or cluster arsenic compounds, for achieving P- and/or As-doping, in the production of doped articles of manufacture, e.g., silicon wafers or precursor structures for manufacturing microelectronic devices.