Semiconductor Trench Electrode with Dual Materials
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Solution Overview
Problem
Current semiconductor devices, such as JFETs, MOSFETs, and IGBTs, face challenges in reducing gate-drain capacitance while maintaining reliability and avoiding increased on-state resistance, as deep trenching for thicker oxide layers can lead to hot carrier injection and reliability issues.
Innovation Solution
A method involving the creation of an insulating block at the trench bottom using self-aligned spacer layers, which protects the insulating layer during processing, allowing for a low gate-drain charge without increasing trench depth, and adjusting the thickness of the insulating block and spacer layers to optimize gate-drain charge.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the trench depth is increased to reduce gate-drain capacitance, then gate-drain charge is reduced, but reliability deteriorates due to hot carrier injection
Solution Approach 1:
The patent applies local quality by creating an insulating block at the trench bottom with different material properties than the rest of the insulating layer. This localized modification allows the trench to be shallower (improving reliability) while still achieving sufficient gate-drain capacitance reduction through the optimized insulating block structure at the critical bottom region.
Solution Approach 2:
The patent changes the parameters of the insulating layer by introducing an insulating block with specific thickness and material composition at the trench bottom. By adjusting the insulating block thickness to be between 1nm-10nm and selecting appropriate dielectric materials, the gate-drain charge is reduced while maintaining reliability, avoiding the need to increase overall trench depth.
2Quantity of substance
If the insulating layer thickness is increased to reduce gate-drain capacitance, then gate-drain charge is reduced, but on-state resistance increases
Solution Approach 1:
The insulating block at the trench bottom provides localized capacitance reduction without increasing the overall insulating layer thickness. This localized approach reduces gate-drain charge while maintaining lower on-state resistance by avoiding the need to thicken the entire insulating layer, which would increase parasitic effects and reduce conductivity.
3Quantity of substance
If the trench depth is increased to improve gate-drain charge characteristics, then gate-drain charge is reduced, but manufacturing complexity increases
Solution Approach 1:
The insulating block is formed as a preliminary structure at the trench bottom before final electrode deposition. This preliminary action of creating the insulating block with controlled thickness (1nm-10nm) simplifies subsequent processing steps and avoids the need for complex deep trench formation and multiple etching steps that would be required to achieve the same gate-drain charge reduction through increased trench depth.
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 enables the production of semiconductor devices with low gate-drain charge and improved reliability, avoiding hot carrier injection risks while maintaining cost-efficiency and reducing on-state resistance.
Implementation Method 1
creating the insulating layer comprises growing a thermal oxide on the trench bottom and on the at least one side wall
Data Source
AI summary
A semiconductor device includes a semiconductor body having a front side and a back side, and a trench included in the semiconductor body. The trench extends into the semiconductor body along an extension direction that points from the front side to the back side. The trench includes an electrode structure and an insulation structure, the insulation structure insulating the electrode structure from the semiconductor body and the electrode structure being arranged for receiving an electric signal from external of the semiconductor device. The electrode structure includes a first electrode and a second electrode in contact with the first electrode, the first electrode including a first electrode material and the second electrode including a second electrode material different from the first electrode material. The first electrode extends further along the extension direction as compared to the second electrode.