Semiconductor Device With Segmented Gate And Insulated Contacts
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Solution Overview
Problem
Transistors in analog circuits face instability in drain current in the saturated region due to hot carrier generation, leading to undesired sub-current flow between the source and drain, which increases drain current with increasing drain voltage.
Innovation Solution
The semiconductor device design includes contacts extending into the n-type layers, with insulating films covering their side surfaces, increasing the resistance path and reducing sub-current flow, along with a subdivided gate electrode and deep trench isolation to minimize gate-drain capacitance and 1/f noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If contacts are extended into the n-type layers to increase resistance path, then sub-current flow is reduced, but device complexity increases due to additional insulating films and contact structures
Solution Approach 1:
The gate electrode is divided into multiple segments (first gate electrode and second gate electrode) separated by an insulating film. This segmentation allows independent control of different regions and reduces gate-drain capacitance, thereby stabilizing drain current in the saturated region while managing the complexity through modular design
Solution Approach 2:
Insulating films are introduced as intermediary elements between the contacts and the n-type layers, and between the gate electrode segments. These intermediaries increase the resistance path to reduce sub-current flow while maintaining electrical isolation, thus improving drain current stability without direct contact between conductive elements
2Reliability
If gate electrode is subdivided to minimize gate-drain capacitance, then drain current stability improves, but manufacturing precision requirements increase
Solution Approach 1:
The gate electrode is segmented into multiple parts with insulating films between them, which reduces gate-drain capacitance and improves drain current stability. The segmentation is designed with overlapping regions that can be aligned using standard photolithography techniques, managing manufacturing precision requirements
Solution Approach 2:
The insulating films are positioned within the overall gate electrode structure, with each insulating film nested between gate electrode segments. This nested arrangement reduces gate-drain capacitance while maintaining a compact structure that can be manufactured with controlled precision
3Reliability
If insulating films are added to cover contact side surfaces, then sub-current flow is reduced, but device complexity and manufacturing steps increase
Solution Approach 1:
Insulating films are applied locally to specific regions where they are most needed - between the gate electrode segments and in contact regions where sub-current flow occurs. This localized application reduces sub-current flow without requiring insulating films throughout the entire device, thus managing complexity
Solution Approach 2:
The insulating films serve multiple functions simultaneously: they increase resistance to reduce sub-current flow, provide electrical isolation between gate electrode segments, and act as spacers for contact alignment. This multi-functionality reduces the need for additional separate structures, managing device complexity
Data Source
AI summary
A semiconductor device includes a semiconductor portion of a first conductivity type, a first semiconductor layer and a second semiconductor layer of a second conductivity type separated from each other and provided in an upper layer portion of the semiconductor portion, a gate electrode provided on the semiconductor portion, a first contact piercing the gate electrode, a second contact piercing the gate electrode, a first insulating film provided between the first semiconductor layer and a side surface of the first contact and between the first contact and the gate electrode, and a second insulating film provided between the second semiconductor layer and a side surface of the second contact and between the second contact and the gate electrode. A lower portion of the first contact is disposed inside the first semiconductor layer, a lower end of the first contact is connected to the first semiconductor layer.