VUV Blocking Layer for High Voltage Transistor Isolation
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Solution Overview
Problem
Semiconductor integrated circuit devices face issues with high voltage driving transistors due to sensitivity to vacuum ultraviolet (VUV) rays, which cause changes in electrical charges leading to increased drain-off current and reduced isolation effects, especially in high voltage transistors with low doping concentrations.
Innovation Solution
Incorporating a VUV blocking layer, such as a nitride or SiON layer, on the semiconductor substrate to absorb VUV rays and prevent charge accumulation on gate insulating and isolation layers, thereby reducing leakage currents and maintaining transistor isolation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the doping concentration of the lightly doped region is reduced to enlarge the depletion region, then the breakdown voltage is increased, but the transistor becomes more sensitive to VUV ray-induced charge accumulation
Solution Approach 1:
A VUV blocking layer is introduced as an intermediary component between the transistor structure and the VUV radiation source. This layer specifically blocks VUV rays while allowing the transistor to maintain its low doping concentration and high breakdown voltage characteristics. The blocking layer absorbs the harmful radiation before it can affect the sensitive lightly doped region, thus resolving the contradiction between achieving high breakdown voltage and maintaining reliability under VUV exposure.
2Reliability
If a VUV blocking layer is added to protect against charge accumulation, then the transistor reliability is improved, but the device complexity increases
Solution Approach 1:
The VUV blocking layer serves multiple functions simultaneously: it blocks VUV radiation to prevent charge accumulation, acts as a protective barrier for the underlying transistor structure, and maintains electrical isolation between adjacent transistors. By combining these functions into a single layer, the design achieves improved reliability without proportionally increasing device complexity.
3Strength
If the gate insulating layer thickness is increased to handle high voltage, then the high voltage transistor can operate normally, but the transistor becomes more susceptible to VUV-induced charge effects
Solution Approach 1:
The VUV blocking layer is positioned as an intermediary between the VUV radiation source and the gate insulating layer. This prevents VUV-induced charge accumulation on the gate insulating layer, allowing it to maintain its designed thickness for high voltage operation without becoming susceptible to radiation effects. The blocking layer absorbs the harmful radiation before it can interact with the gate insulating layer.
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 VUV blocking layer effectively blocks VUV radiation, reducing drain-off and isolation currents, thereby enhancing the operating characteristics and stability of high voltage transistors by preventing unwanted charge accumulation and maintaining isolation between transistors.
Implementation Method 1
Incorporating a VUV blocking layer, such as a nitride or SiON layer, on the semiconductor substrate to absorb VUV rays and prevent charge accumulation on gate insulating and isolation layers
Data Source
AI summary
Provided are a semiconductor integrated device and a method for fabricating the same. The semiconductor integrated circuit includes a semiconductor substrate including a first dopant, a first conductive layer pattern formed on the semiconductor substrate, an interlayer dielectric layer formed on the first conductive layer pattern, a second conductive layer pattern formed on the interlayer dielectric layer, and a first vacuum ultraviolet (VUV) blocking layer which blocks a VUV ray radiated to the semiconductor substrate.