SiCr Ring Resistor Structure for Low-TCR Chip Isolation
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Solution Overview
Problem
Polysilicon resistors in integrated chips face issues such as high temperature coefficient of resistance (TCR) leading to resistance changes over time, especially in high voltage applications, resulting in device failure due to high heat accumulation and low breakdown voltage.
Innovation Solution
A resistor structure is fabricated using silicon chromium (SiCr) with a reduced TCR, and a method is developed to form the resistor structure by forming a resistive layer, conductive contact layer, and dielectric structure, followed by patterning processes to create ring structures that laterally enclose and isolate resistor segments, reducing the number of patterning steps and associated costs and time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If polysilicon resistors are used in integrated chips, then the device can be manufactured with standard processes, but the temperature coefficient of resistance is high leading to resistance changes over time and device failure in high voltage applications
Solution Approach 1:
The patent changes the material parameter from polysilicon to silicon chromium (SiCr) alloy, which fundamentally alters the temperature coefficient of resistance from high to low values. This material substitution directly resolves the contradiction by maintaining resistance stability while eliminating the harmful thermal effects that cause device failure in high voltage applications.
Solution Approach 2:
The invention uses a composite silicon chromium alloy material instead of pure polysilicon. The composite nature of SiCr provides both the electrical conductivity needed for resistor function and the low temperature coefficient of resistance, thereby simultaneously achieving reliability and resistance to thermal harmful factors.
2Manufacturing precision
If multiple patterning processes are used to form resistor structures, then the resistor segments can be precisely isolated, but the fabrication time and cost increase
Solution Approach 1:
The patent combines multiple patterning operations into a single patterning process that simultaneously defines both the resistor segments and the ring structures. This merging of operations achieves precise isolation of resistor segments while eliminating the time loss associated with sequential patterning steps, directly resolving the contradiction between manufacturing precision and fabrication time.
Solution Approach 2:
The single patterning process performs multiple functions: it defines the resistor segment boundaries, creates the ring structures, and establishes the spatial relationships between different resistor elements. This multi-functional approach achieves precise isolation without requiring multiple dedicated patterning steps, thereby reducing fabrication time while maintaining manufacturing precision.
Data Source
AI summary
Various embodiments of the present disclosure are directed towards an integrated chip including a resistor layer over a substrate. An isolation structure contacts a first pair of opposing sidewalls of the first resistor layer. The isolation structure includes a body structure and a liner layer disposed on opposing sidewalls of the body structure.