Capacitor Unit with Control Layer Patterns for VCC Reduction
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Solution Overview
Problem
The size reduction of capacitors in semiconductor devices is limited by the high voltage coefficient of capacitance (VCC) in existing dielectric materials, making it challenging to achieve high integration and precision in analog circuits.
Innovation Solution
A capacitor unit is designed with a multilayer structure and control layer patterns to reduce the VCC, comprising metal or metal nitride electrodes and dielectric layers like hafnium oxide and hafnium carbon oxynitride, with control layers formed by oxidation processes to minimize the voltage-dependent capacitance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a high-k dielectric material is used for the dielectric layer, then the capacitance increases and the capacitor size decreases, but the voltage coefficient of capacitance (VCC) increases
Solution Approach 1:
The capacitor is divided into multiple capacitors connected in series, each with its own control layer pattern. This segmentation allows the VCC of individual capacitors to be controlled and combined to achieve a lower overall VCC while maintaining high capacitance through the high-k dielectric material
Solution Approach 2:
Control layer patterns are formed locally on specific electrodes (first and second lower electrodes) rather than uniformly throughout the structure. These localized control layers selectively modulate the electric field in critical regions to reduce VCC without compromising the overall high capacitance provided by the high-k dielectric
2Ease of manufacture
If a polysilicon-insulator-polysilicon (PIP) structure is used, then the capacitor can be formed, but the VCC cannot be sufficiently decreased due to depletion area
Solution Approach 1:
The invention changes the material parameters by replacing polysilicon electrodes with metal or metal nitride electrodes, and introducing control layer patterns with specific dielectric properties. This parameter change eliminates the depletion area effect inherent in polysilicon while maintaining manufacturability through standard deposition processes
Solution Approach 2:
Control layer patterns act as intermediary elements between the metal electrodes and the high-k dielectric layer. These control layers mediate the electric field distribution to reduce VCC without interfering with the fundamental metal-insulator-metal structure and its manufacturing advantages
3Reliability
If a metal-insulator-metal (MIM) structure is used, then the VCC is smaller than PIP structure, but the VCC is still not sufficiently small for high precision analog applications
Solution Approach 1:
The MIM capacitor structure is segmented into multiple capacitors connected in series, each contributing to the overall VCC reduction. The total VCC of the capacitor unit is the sum of VCCs of individual capacitors, and by optimizing each segment, the overall precision for analog applications is achieved
Solution Approach 2:
The invention uses composite material structures combining metal electrodes, control layer patterns, and high-k dielectric layers. This composite approach integrates the low VCC advantage of MIM structures with the high capacitance density of high-k materials, achieving both low VCC and high precision required for analog applications
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 solution effectively reduces the VCC by forming control layer patterns on electrodes and connecting capacitors in series, resulting in a capacitor with a small VCC and large capacitance, suitable for high-precision analog applications.
Implementation Method 1
a first control layer pattern for controlling a VCC of the first capacitor. The first control layer pattern is formed between the first lower electrode and the first dielectric layer pattern
Implementation Method 2
control layers formed by oxidation processes to minimize the voltage-dependent capacitance
Data Source
AI summary
A capacitor unit includes a first capacitor and a second capacitor. The first capacitor includes a first lower electrode, a first dielectric layer pattern and a first upper electrode sequentially stacked. The first capacitor includes a first control layer pattern for controlling a voltage coefficient of capacitance (VCC) of the first capacitor between the first lower electrode and the first dielectric layer pattern. The second capacitor includes a second lower electrode, a second dielectric layer pattern and a second upper electrode sequentially stacked. The second lower electrode is electrically connected to the first upper electrode, and the second upper electrode is electrically connected to the second lower electrode. The second capacitor includes a second control layer pattern for controlling a VCC of the second capacitor between the second lower electrode and the second dielectric layer pattern.