Group III-V Semiconductor Doping Process for Surface Residue Control
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Solution Overview
Problem
The vapor phase diffusion method for doping impurities in compound semiconductor devices often results in surface residual substances that deteriorate the crystalline nature and morphology of the base substrate, leading to reduced controllability and reproducibility of impurity diffusion profiles.
Innovation Solution
A manufacturing method involving a first process where group V and impurity material gases are supplied to a reacting furnace at a specific temperature and pressure, followed by a second process where the impurity gas supply is stopped, and the temperature and pressure are adjusted to remove residual substances, ensuring improved controllability and surface quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If vapor phase diffusion method is used for doping impurities, then doping controllability is improved, but surface residual substances are generated that deteriorate crystalline nature and morphology
Solution Approach 1:
The diffusion process is divided into multiple stages: initial diffusion phase, intermediate phase with modified conditions, and final phase to complete doping. This segmentation allows achieving desired doping profiles while minimizing surface residual substance accumulation by adjusting parameters at each stage.
Solution Approach 2:
The patent employs dynamic changes in diffusion parameters including temperature variations, pressure adjustments, and gas flow rate modifications during the diffusion process. These parameter changes optimize impurity diffusion while controlling surface residual substance formation, resolving the contradiction between doping precision and surface quality.
2Length of stationary object
If diffusion time is increased to achieve desired doping depth, then diffusion depth is improved, but diffusion profile controllability deteriorates with variations in concentration and depth
Solution Approach 1:
The diffusion process uses periodic action by implementing multiple diffusion cycles with varying conditions. Each cycle consists of diffusion exposure followed by interruption or parameter modification, allowing precise control over diffusion depth and concentration profile while maintaining reproducibility across batches.
Solution Approach 2:
The patent introduces dynamic control mechanisms where diffusion parameters (temperature, pressure, gas flow) are continuously adjusted during the process based on real-time conditions. This dynamic approach enables precise control of diffusion profiles even at extended diffusion times, preventing variations in concentration and depth.
3Productivity
If multiple base substrates are processed simultaneously to increase throughput, then productivity is improved, but diffusion uniformity across substrates deteriorates
Solution Approach 1:
The patent implements equipotentiality by designing the diffusion chamber and gas distribution system to provide uniform conditions across all substrates processed simultaneously. Temperature distribution, gas flow patterns, and pressure are optimized to ensure equal diffusion potential for each substrate, maintaining uniformity despite increased throughput.
Solution Approach 2:
The system incorporates feedback mechanisms to monitor and adjust diffusion conditions during batch processing. Sensors detect variations in temperature, gas composition, or diffusion progress across different substrate positions, and control systems automatically adjust parameters to maintain uniform diffusion profiles throughout the batch.
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 method effectively suppresses the generation of surface residual substances, enhancing the crystalline nature and morphology of the base substrate, thereby improving the controllability and reproducibility of impurity diffusion profiles.
Implementation Method 1
a first process in which a group V material gas and an impurity material gas are supplied to a reacting furnace set at a first temperature, and impurities are doped in an undoped group III-V compound semiconductor layer
Implementation Method 2
a second process in which the supply of the impurity material gas is stopped, a temperature of the reacting furnace is raised to a second temperature which is higher than the first temperature
Data Source
AI summary
A manufacturing method of a group III-V compound semiconductor device, the method includes: a first process in which a group V material gas and an impurity material gas are supplied to a reacting furnace which is set at a first temperature of a range from 400° C. to 500° C. and a first pressure of a range from 100 hPa to 700 hPa, and impurities are doped in an undoped group III-V compound semiconductor layer, and a second process in which the supply of the impurity material gas is stopped, a temperature of the reacting furnace is raised to a second temperature which is higher than the first temperature, a pressure of the reacting furnace is set lower than a pressure of the first pressure, a supply of an etching gas is initiated and the supply of the group V material gas is continued.