Zirconium Oxide Capacitor Dielectric Phase Tuning for DRAM Capacitance
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Solution Overview
Problem
In the development of smaller semiconductor devices like DRAM, it is challenging to manufacture capacitors with higher capacitance without increasing leakage current or significantly raising manufacturing costs.
Innovation Solution
A method for manufacturing a semiconductor structure involves forming a capacitor dielectric layer with at least one zirconium oxide layer, followed by a microwave annealing treatment to convert the zirconium oxide crystal phase to a tetragonal phase, thereby increasing the dielectric constant and capacitance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the capacitor size is reduced to enable smaller semiconductor devices, then the device scale is improved, but the capacitance decreases
Solution Approach 1:
The patent changes the crystal phase parameter of zirconium oxide from monoclinic to tetragonal through microwave annealing treatment. This parameter change increases the dielectric constant of the capacitor dielectric layer, thereby increasing capacitance without increasing device size. The tetragonal phase of ZrO2 provides higher dielectric performance compared to the monoclinic phase, resolving the contradiction between device miniaturization and capacitance maintenance.
2Quantity of substance
If the dielectric layer thickness is reduced to increase capacitance density, then the capacitance per unit area is improved, but the leakage current increases
Solution Approach 1:
The patent changes the material parameter by converting zirconium oxide to its tetragonal crystal phase, which has superior dielectric properties including higher dielectric constant and lower leakage current compared to the monoclinic phase. This material parameter change allows for thinner dielectric layers with reduced leakage, thereby increasing capacitance density without proportionally increasing leakage current.
Solution Approach 2:
The patent utilizes phase transition of zirconium oxide from monoclinic to tetragonal phase through microwave annealing. The tetragonal phase exhibits better dielectric characteristics with lower leakage current, enabling the use of thinner dielectric layers while maintaining acceptable leakage levels and achieving higher capacitance density.
3Ease of manufacture
If conventional annealing methods are used to treat the capacitor dielectric layer, then the manufacturing process is simple, but the dielectric constant of zirconium oxide is insufficient
Solution Approach 1:
The patent replaces conventional thermal annealing methods with microwave annealing treatment. Microwave annealing directly excites the material molecules to generate heat internally, enabling efficient phase transformation of zirconium oxide to tetragonal phase. This substitution achieves higher dielectric constant while maintaining manufacturing simplicity and potentially reducing processing time and temperature compared to conventional methods.
Solution Approach 2:
The patent induces phase transition of zirconium oxide from monoclinic to tetragonal phase through microwave annealing. The tetragonal phase has inherently higher dielectric constant, thus achieving improved capacitance without complicating the manufacturing process. The microwave annealing provides a straightforward method to achieve this phase transition.
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 method effectively increases the dielectric constant of zirconium oxide and the capacitance of the semiconductor structure without changing the material, making it suitable for small-scale semiconductor devices like DRAM and cost-effective for large-scale industrial production.
Implementation Method 1
The capacitor dielectric layer is subjected with a microwave annealing treatment, to convert a crystal phase of zirconium oxide to a tetragonal crystal phase
Implementation Method 2
The capacitor dielectric layer is subjected with a microwave annealing treatment
Implementation Method 3
A capacitor is used to store data. The capacitor is an electronic element for storing energies in the form of electrostatic field
Data Source
AI summary
A method for manufacturing a semiconductor structure includes the following operations. A substrate is provided. A lower electrode is formed on the substrate. A capacitor dielectric layer is formed on a surface of the lower electrode. The capacitor dielectric layer includes at least one zirconium oxide layer. The capacitor dielectric layer is subjected with microwave annealing treatment to convert a crystal phase of zirconium oxide to a tetragonal crystal phase. An upper electrode is formed on a surface of the capacitor dielectric layer.