Oxide-Nitride Trench Stack for Radiation-Hardened Semiconductors
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Semiconductor devices exposed to high radiation levels, such as cosmic rays, face increased oxide trapped charges and interface trap density, leading to reduced reliability and performance, as thicker oxide layers provide protection against Single Event Effects but weaken the device against Total Ionizing Dose.
Innovation Solution
A semiconductor device design featuring trenches with oxide and nitride layers, sealed with a dielectric material, and doped regions to enhance radiation resistance, including a trench oxide layer in contact with the sidewall and bottom, and a trench nitride layer covering the sidewall, which helps in maintaining device integrity under radiation exposure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If thicker oxide layers are used to protect against Single Event Effects, then radiation-induced electric field is reduced, but the device becomes weaker against Total Ionizing Dose
Solution Approach 1:
The oxide layer is segmented into multiple thin oxide layers separated by nitride layers, creating an oxide-nitride stack structure. This segmentation allows each thin oxide layer to maintain low trapped charge while the nitride layers provide field screening to protect against Total Ionizing Dose, resolving the contradiction between SEE protection and TID resistance
Solution Approach 2:
The patent uses a composite structure combining oxide and nitride materials in alternating layers. The oxide layers provide dielectric functionality with low trapped charge, while the nitride layers provide high breakdown strength and field screening, creating a composite material system that simultaneously addresses both radiation damage mechanisms
2Object-affected harmful factors
If thicker oxide layers are used to reduce oxide trapped charges, then Single Event Effect protection is improved, but interface trap density increases under radiation exposure
Solution Approach 1:
The oxide layer is divided into multiple thin oxide layers separated by nitride layers. Each thin oxide layer has reduced trapped charge compared to a single thick oxide layer, and the nitride layers act as barriers that prevent trap formation at oxide-silicon interfaces, simultaneously reducing both oxide trapped charges and interface trap density
Solution Approach 2:
The nitride layers serve as intermediary layers between the oxide layers and the silicon substrate. These nitride layers mediate the radiation damage by providing a buffer that prevents charge trapping at critical interfaces and screens electric fields, reducing both oxide trapped charges and interface trap density
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 proposed design effectively reduces oxide trapped charges and interface trap density, enhancing the semiconductor device's ability to withstand radiation-induced damage, thereby improving its reliability and performance in harsh environments.
Implementation Method 1
A trench oxide layer is in contact with at least the sidewall and the bottom of the trench. A trench nitride layer covers the trench oxide layer at least on the sidewall of the trench
Implementation Method 2
A dielectric seal material seals the trench proximate the first main surface of the semiconductor layer such that the trench is air-tight
Data Source
AI summary
A semiconductor device includes a semiconductor layer with opposing first and second main surfaces and a first column extending from the first main surface and having a first concentration of a dopant of the first conductivity type. A trench with a sidewall and bottom extends at least partially through the semiconductor layer from the first main surface. A second column between the trench sidewall and the first column has a second concentration of a dopant of a second conductivity type and is formed in the semiconductor layer and extends from the first main surface. A trench oxide layer is in contact with at least the trench sidewall and the trench bottom. A trench nitride layer covers the trench oxide layer at least on the trench sidewall. A dielectric seal material seals the trench proximate the first main surface of the semiconductor layer such that the trench is air-tight.