Interleaved Nanosheet Diode Structure for Higher PN Junction Conductivity
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Solution Overview
Problem
Existing nanosheet semiconductor device fabrication methods face challenges in forming diodes with enhanced conductivity, as dielectric spacers often remain embedded between p-doped and n-doped semiconductor structures, affecting the PN junction formation and overall device performance.
Innovation Solution
The formation of a nanosheet diode with a bookend structure doped as one anode/cathode and a central structure doped as the other, featuring interleaved nanosheets that directly contact the central structure's surfaces, along with specific doping and epitaxial growth techniques to enhance conductivity and isolate the diode from adjacent transistors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If dielectric spacers are used during nanosheet diode fabrication, then the manufacturing process is simplified, but the embedded spacers remain between doped structures reducing conductivity
Solution Approach 1:
The patent removes dielectric spacers from the final diode structure through selective etching processes. The spacers are temporarily introduced during fabrication to define regions, then completely removed after serving their purpose, eliminating the conductivity barrier they create between doped nanosheets.
Solution Approach 2:
The patent performs preliminary doping of nanosheets before spacer removal, ensuring that when spacers are eventually removed, the doped regions are already in place to immediately form conductive paths. This sequencing ensures conductivity enhancement is ready once the spacer barrier is eliminated.
2Reliability
If interleaved nanosheet structures are formed, then conductivity is enhanced, but the device complexity increases
Solution Approach 1:
The patent divides the diode structure into multiple discrete nanosheet segments that are interleaved between doped bookend structures. Each nanosheet segment can be independently formed and controlled, allowing conductivity enhancement through increased interface area while maintaining manufacturability through modular fabrication processes.
Solution Approach 2:
The patent nests multiple nanosheets within the diode structure, with nanosheets positioned between and connected to bookend structures. This nested arrangement creates multiple conductive pathways in a compact volume, enhancing conductivity without proportionally increasing the device footprint or overall complexity.
3Reliability
If bookend structures with direct contact to central structure surfaces are formed, then conductivity is improved, but manufacturing precision requirements increase
Solution Approach 1:
The patent uses the nanosheet structures as intermediary elements between the bookend structures. These nanosheets provide a compliant interface that can accommodate minor misalignments while still achieving effective electrical contact, reducing the stringency of manufacturing precision requirements for direct bookend-to-bookend contact.
Solution Approach 2:
The patent controls the physical and chemical parameters of the nanosheet interfaces, such as surface area, doping concentration, and material composition, to optimize contact resistance. By adjusting these parameters, the system achieves high conductivity even with moderate manufacturing tolerances in the mechanical alignment of bookend structures.
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 results in nanosheet diodes with improved conductivity and effective isolation, enabling enhanced performance by directly contacting the bookend structure with the central structure's surfaces and utilizing specific doping and epitaxial growth to optimize conductivity and isolation.
Implementation Method 1
a bookend structure that is doped as one of the anode and the cathode of the diode, and a central structure that is doped as the other of the anode and the cathode of the diode
Implementation Method 2
implanting epitaxial material with another dopant to form PN junctions
Data Source
AI summary
A nanosheet diode includes a bookend structure and a central structure. The bookend includes a first semiconductor that is doped as one of the anode and the cathode of the diode, and includes a left block, a right block, and a first stack of spaced-apart nanosheets that horizontally connect the left and right blocks. The central structure includes a second semiconductor that is doped as the other of the anode and the cathode of the diode, and includes a front block, a rear block, and a second stack of nanosheets that are interleaved crosswise into spaces between the first stack of spaced-apart nanosheets and that horizontally connect the front and rear blocks. The bookend structure directly contacts top, bottom, and end surfaces of the second stack of nanosheets of the central structure.