Carbon-Oxygen Doped Polysilicon Resistors for Stable IC Matching
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Solution Overview
Problem
Polysilicon resistors in integrated circuits face limitations due to insufficient resistance values, excessive resistance drift with temperature and use duration, and inadequate matching, which restrict the functionality of ICs.
Innovation Solution
The formation of polysilicon resistors doped with carbon and/or oxygen, either through in-situ doping during deposition or subsequent implantation, to enhance resistance stability and matching, with specific doping concentrations and processes like CVD and annealing to achieve uniform distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional polysilicon resistors are used, then manufacturing process is simple, but resistance values drift excessively with temperature and use duration
Solution Approach 1:
The patent applies parameter changes by introducing carbon and oxygen dopants at controlled concentrations during polysilicon deposition. This changes the electrical properties of the polysilicon material, achieving stable resistance values that do not drift with temperature or use duration. The doping parameters (concentration, timing) are precisely controlled to achieve the desired resistance stability.
Solution Approach 2:
The patent creates a composite material structure by incorporating carbon and oxygen elements into the polysilicon matrix. This composite approach (polysilicon + carbon/oxygen dopants) produces a material with superior resistance stability compared to conventional undoped polysilicon, while maintaining compatibility with existing manufacturing processes.
2Adaptability or versatility
If resistor size is reduced to increase IC functionality, then IC functionality improves, but resistance values become insufficient
Solution Approach 1:
The patent changes the material parameters of polysilicon through carbon and oxygen doping, which fundamentally alters the resistance characteristics. This allows small-sized resistors to achieve sufficient and precise resistance values that would be impossible with conventional polysilicon, thereby enabling increased IC functionality without sacrificing resistance precision.
3Manufacturing precision
If doping concentration is increased to improve resistance matching, then resistance matching improves, but manufacturing process complexity increases
Solution Approach 1:
The patent applies preliminary action by incorporating carbon and oxygen dopants during the polysilicon deposition process itself, rather than requiring subsequent separate doping steps. This integrated approach achieves excellent resistance matching while avoiding the additional process complexity that would result from multiple sequential doping operations.
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 carbon and/or oxygen doping significantly reduces resistor drift and improves resistance matching, achieving more stable and uniform resistance values across ICs, as demonstrated by experimental results.
Implementation Method 1
depositing polysilicon and doping the deposited polysilicon with a carbon dopant and/or an oxygen dopant
Implementation Method 2
specific doping concentrations and processes like CVD and annealing to achieve uniform distribution
Data Source
AI summary
Apparatus, and their methods of manufacture, that include an insulating feature above a substrate and a resistor formed on the insulating feature. Forming the resistor includes depositing polysilicon and doping the polysilicon (e.g., in-situ) with a carbon dopant and/or an oxygen dopant.