Integrated Gate Dielectric for High-Voltage Transistor Insulation
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Solution Overview
Problem
In advanced semiconductor manufacturing processes, such as the 28-nm technology, the thickness of the gate oxide in high-voltage transistors becomes thicker than the dielectric layer, leading to insulation issues and potential physical contact between the gate and metal layers, which can cause abnormal transistor operation and damage.
Innovation Solution
The insulating layer is utilized as both a gate oxide and a dielectric layer, allowing it to be thinner than 1200 angstroms, while the patterned conductive layer serves as a gate electrode integrated within the metal-1 layer for routing, eliminating the need for spacers and simplifying the manufacturing process without affecting breakdown voltages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the gate oxide thickness is increased to sustain high voltage, then the breakdown voltage is improved, but the gate oxide becomes thicker than the dielectric layer causing insulation issues and potential physical contact between gate and metal layers
Solution Approach 1:
The patent merges the gate oxide layer and the first dielectric layer into a single integrated structure. The gate oxide is formed between the gate electrode and the semiconductor substrate, while the first dielectric layer is formed between the gate electrode and the metal layer, with these two dielectric regions combined into one continuous layer. This eliminates the need for separate gate oxide and dielectric layers, allowing the gate electrode to be fully covered by a unified dielectric structure that provides both electrical insulation and physical separation, thereby preventing contact between the gate and metal layers while sustaining high breakdown voltages.
Solution Approach 2:
The unified dielectric layer serves multiple functions simultaneously: it acts as the gate oxide providing electrical insulation between the gate electrode and semiconductor substrate, and as the first dielectric layer providing physical separation between the gate electrode and metal layer. This multi-functional design eliminates the need for separate components and resolves the contradiction between achieving high breakdown voltage and preventing physical contact.
2Reliability
If spacers are added to prevent gate-metal contact, then insulation is improved, but the manufacturing process complexity increases
Solution Approach 1:
The patent combines the gate oxide formation and dielectric layer formation into a single manufacturing step. Instead of forming separate gate oxide and dielectric layers that would require additional alignment and deposition steps, the process forms a unified dielectric layer that simultaneously serves both functions. This eliminates the need for spacers and reduces manufacturing complexity while maintaining reliable insulation.
3Reliability
If the dielectric layer thickness is increased to prevent physical contact, then insulation is improved, but the device size increases violating size requirements
Solution Approach 1:
By merging the gate oxide and dielectric layer into a single unified structure, the patent optimizes the thickness of the dielectric region. The unified layer provides both electrical insulation and physical separation functions, allowing for a thinner overall structure compared to having separate gate oxide and dielectric layers with gaps. This reduces device size while maintaining adequate insulation and preventing gate-metal contact.
Data Source
AI summary
A semiconductor device includes a transistor. The transistor includes an active region in a substrate, a patterned conductive layer being a portion of an interconnection layer for routing, and an insulating layer extending over the substrate and configured to insulate the active region from the patterned conductive layer. The patterned conductive layer and the insulating layer serve as a gate of the transistor.