Shielded Semiconductor Junctions Preventing Charge Leakage
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Solution Overview
Problem
Semiconductor devices face issues with undesirable charge accumulation on their surfaces, leading to electric field offsets, oxide breakdown, and conductive channel formation, which are exacerbated by shrinking device geometries and increased performance demands, and current methods are either costly or limited to manufacturing protection.
Innovation Solution
A cost-effective conductive shield with a novel geometry is introduced, laterally separated from metal interconnects to terminate electromagnetic fields induced by accumulated charge, preventing the formation of conductive channels between junctions without requiring additional isolation or modifying existing fabrication processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If shielding of the entire device is used to prevent charge accumulation, then charge-induced leakage is prevented, but device complexity and manufacturing cost increase due to additional isolation and processing steps
Solution Approach 1:
The shield is segmented into a first portion and a second portion separated by a gap. The first portion is disposed over a first doped junction and the second portion is disposed over a second doped junction, with the gap positioned between them. This segmentation prevents conductive channel formation between junctions while avoiding the need for complete device shielding, thus reducing complexity and manufacturing steps.
Solution Approach 2:
Instead of applying uniform shielding across the entire device, the shield is locally applied only over specific doped junctions where charge accumulation poses a risk. This localized approach targets the critical areas needing protection while leaving other regions unaffected, thereby reducing overall device complexity and processing requirements.
2Power
If device geometries are shrunk to meet performance demands, then device performance increases, but tolerance for charge accumulation decreases making devices more susceptible to leakage
Solution Approach 1:
The shield structure is implemented in advance during fabrication to counteract the increased susceptibility to charge accumulation that results from geometry shrinkage. By positioning shield portions over doped junctions with gaps between them, the design proactively prevents conductive channel formation before charge accumulation can cause leakage, thus maintaining reliability despite smaller feature sizes.
3Reliability
If current protection methods are used during manufacturing, then charge accumulation is prevented during fabrication, but protection is limited only to manufacturing phase and not during device usage
Solution Approach 1:
The shield structure serves multiple functions across different phases of device lifecycle. During manufacturing, it prevents charge accumulation from reactive ion etching and other electric field-based processes. During device usage, it continues to protect against stray electromagnetic coupling and charge accumulation. The same physical structure provides protection in both manufacturing and operational phases, eliminating the need for separate protection mechanisms.
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
The shield effectively prevents charge-induced leakage and conductive channel formation, ensuring reliable device performance across manufacturing and usage phases, while minimizing additional processing steps and costs.
Implementation Method 1
A shield bias is connected to the shield to terminate an electromagnetic field on a surface of the shield
Data Source
AI summary
A structure for preventing charge induced leakage of a semiconductor device includes a shield separated from a first interconnect by at least a first lateral spacing and separated from a second interconnect by at least a second lateral spacing. The first interconnect is connected to a first junction and the second interconnect is connected to a second junction. A shield bias is connected to the shield to terminate an electromagnetic field on the shield. The shield between the first and second lateral spacings has a minimum width to substantially prevent formation of a conductive channel between the first and second junctions. The shield may be formed over a portion of the first junction and over a portion of the second junction to substantially prevent formation of another conductive channel between the first and second junctions at a location that does not have the first and second lateral spacings.