Spin Qubit Gate Array Contacting With Dielectric Spacers
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Solution Overview
Problem
Contacting closely spaced gates in semiconductor spin qubit quantum dot devices is challenging due to misalignment errors and the risk of shorting, which traditional damascene-type methods cannot effectively address.
Innovation Solution
A method involving the formation of conformal dielectric spacers on sidewalls of conductive lines, allowing for separate process steps to connect gate structures of different types while maintaining isolation despite misalignment, using a conformal dielectric layer to prevent shorting between conductive lines.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional damascene-type methods are used for producing conductive vias and lines, then the manufacturing process is relatively simple, but misalignment errors occur having the same order of magnitude as the gate interspacing, leading to unacceptable misalignment errors and risk of shorting
Solution Approach 1:
The patent divides the gate array into alternating first and second type gates, and separately forms conductive lines for each gate type. This segmentation allows independent alignment processes for each line type, improving precision by eliminating cumulative alignment errors that would occur in traditional single-process damascene methods.
Solution Approach 2:
The patent forms a conformal dielectric layer on the first conductive lines before forming the second conductive lines. This preliminary action creates a protective spacer that compensates for potential misalignment, ensuring that even if alignment errors occur, the conductive lines will not short circuit.
2Reliability
If gates are closely spaced to enable quantum dot confinement, then quantum dot formation is enabled, but the risk of shorting between conductive lines increases due to misalignment
Solution Approach 1:
The patent introduces a conformal dielectric layer as an intermediary between the first and second conductive lines. This intermediary layer acts as a protective spacer that physically separates the conductive lines, preventing shorting even when misalignment occurs, thus maintaining isolation reliability in closely spaced gate structures.
Solution Approach 2:
The conformal dielectric layer provides localized protection at critical interfaces between conductive lines. By applying the dielectric material conformally to the sidewalls of first conductive lines, the patent creates enhanced isolation precisely where shorting risk is highest, without adding bulk material elsewhere.
3Manufacturing precision
If separate process steps are used for different gate types, then alignment precision is improved, but the number of process steps increases
Solution Approach 1:
The patent merges the formation of conformal dielectric layers with the conductive line formation process. By integrating the dielectric layer deposition into the existing fabrication sequence, the patent achieves improved alignment precision through separate processing of first and second type gates while minimizing the increase in total process steps.
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
Ensures reliable electrical connections to gate structures of varying types, preventing shorting and ensuring coherence in qubit operations by maintaining isolation between conductive lines, even with misalignment errors.
Implementation Method 1
a conformal dielectric layer is formed on the first conductive lines, i.e. on a top surface and on sidewalls of the first conductive lines
Implementation Method 2
The conformal layer is configured, for example in terms of its material and thickness, so that it forms a protective spacer on the sidewalls of the first conductive lines
Data Source
AI summary
An array of gate structures is produced on a planar surface, the array being suitable for the production of a spin qubit quantum dot device. The gate structures include alternately arranged structures of a first and second type. According to the example embodiments, electrical connections to the gate structures of the first and second type are produced in separate process step sequences. The connections to the first gate type include the formation of first conductive lines running essentially parallel to the planar surface and connected to the gate structures of the first type by first via connections. Before producing similar connections to the gate structures of the second type, a conformal dielectric layer is formed on the first conductive lines. The conformal layer is configured so that it forms a protective spacer on the sidewalls of the first conductive lines during processing of the second conductive lines, to avoid shorting.