Bandgap Voltage Stabilization via Polysilicon Resistor Layout
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Solution Overview
Problem
Current bandgap reference circuits fail to achieve the target voltage of 1.2 V, with existing verification methods like resistor matching, I/O device matching, and bipolar junction transistor matching only reaching 1.11 V, indicating a need for a new approach to stabilize voltage.
Innovation Solution
The method involves creating multiple layout patterns with reduced polysilicon resistor widths, specifically shrinking the first layout pattern by 2% to 16% to generate corresponding voltage patterns, and matching these patterns with a target voltage to achieve stable output.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional verification methods (resistor matching, I/O device matching, BJT matching) are used, then the bandgap reference circuit can be manufactured with standard processes, but the output voltage only reaches 1.11 V instead of the target 1.2 V
Solution Approach 1:
The patent applies parameter changes by adjusting the critical dimension (width) of polysilicon resistor patterns in the layout. By reducing the width parameter of the first layout pattern to generate a second layout pattern, the resistance value changes, thereby adjusting the bandgap voltage from 1.11 V to the target 1.2 V. This direct parameter modification resolves the voltage discrepancy without requiring complex new verification methods.
2Manufacturing precision
If the polysilicon resistor width is reduced to increase voltage, then the target voltage of 1.2 V can be achieved, but the manufacturing precision requirements increase
Solution Approach 1:
The patent applies preliminary action by performing layout pattern optimization before the actual manufacturing process. The second layout pattern with adjusted critical dimension is prepared and verified in advance through simulation and analysis, ensuring that the voltage target of 1.2 V can be achieved. This preliminary preparation allows for better control of measurement precision during fabrication.
Data Source
AI summary
A method for stabilizing bandgap voltage includes the steps of: providing a first layout pattern designated with a first voltage; reducing a critical dimension of the first layout pattern for generating a second layout pattern corresponding to a second voltage; matching the second voltage with a target voltage; and then outputting the second layout pattern to a mask. Preferably, the first layout pattern and the second layout pattern include polysilicon resistor patterns.