Vertical Diode Fabrication via Low-Temperature Ion Implantation
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Solution Overview
Problem
As semiconductor devices become highly integrated, there is a need to reduce the area occupied by their elements, and existing methods struggle to efficiently form vertical diodes without high-temperature processes that can degrade the semiconductor substrate.
Innovation Solution
A method of fabricating semiconductor devices that includes forming well and impurity regions in a semiconductor substrate, etching to create specific patterns, and using a metal-semiconductor compound layer to improve electrical characteristics, all while avoiding high-temperature processes like selective epitaxial growth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If selective epitaxial growth is used to form vertical diodes, then the diode structure can be formed, but the semiconductor substrate is degraded due to high temperature processing
Solution Approach 1:
The patent changes the temperature parameter from high-temperature selective epitaxial growth to low-temperature ion implantation and thermal annealing processes. Specifically, ion implantation is performed at room temperature or low temperature, followed by rapid thermal annealing at moderate temperatures (e.g., 600-900°C for short durations), which forms the vertical diode structure without subjecting the substrate to prolonged high-temperature exposure that would cause degradation.
2Productivity
If element area is reduced for high integration, then device density increases, but manufacturing precision becomes more difficult to maintain
Solution Approach 1:
The patent transitions from planar diode structures to vertical diode structures by adding the depth dimension. The diode is formed with a vertical junction extending from the surface into the substrate, allowing the active area to be concentrated in a vertical column rather than spread horizontally. This enables higher integration density while maintaining adequate manufacturing precision through standardized photolithography and ion implantation processes.
Solution Approach 2:
The patent applies local quality by creating highly doped regions (e.g., n+ and p+ regions) in specific localized areas through ion implantation. The impurity concentration is dramatically increased in the vertical diode regions compared to surrounding areas, enabling precise control of electrical characteristics at the desired location without affecting adjacent structures, thus maintaining manufacturing precision even as device density increases.
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 allows for the formation of vertical diodes without degrading the semiconductor substrate and enhances the electrical performance of word lines by forming metal-semiconductor compounds, improving the overall efficiency and reliability of semiconductor devices.
Implementation Method 1
forming metal-semiconductor compounds
Data Source
AI summary
A method of fabricating a semiconductor device includes forming a well impurity region, a lower impurity region and an upper impurity region in a semiconductor substrate. The lower impurity region has a different conductivity type than a conductivity type of the well impurity region, the upper impurity region has a different conductivity type than the conductivity type of the lower impurity region, and the upper impurity region has a same conductivity type as the conductivity type of the well impurity region and has a higher impurity concentration than an impurity concentration of the well impurity region. The semiconductor substrate is etched to form lower semiconductor patterns, upper semiconductor patterns upwardly projecting from predetermined regions of the lower semiconductor patterns. An isolation layer filling the first and second spaces between the lower semiconductor patterns and between the upper semiconductor patterns, respectively is formed.