Crystallized Hafnium Oxide Electron Trap Layer for Threshold Adjustment
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Solution Overview
Problem
The miniaturization of transistors leads to deterioration of electrical characteristics such as on-state current, off-state current, threshold, and subthreshold swing, and existing technologies struggle to maintain reliable performance and low power consumption while integrating semiconductor devices.
Innovation Solution
A semiconductor device with a crystallized hafnium oxide electron trap layer is introduced, which includes electrons trapped by setting a higher potential for the gate electrode, allowing for adjustment of the threshold voltage and improved electrical characteristics, and is manufactured using a sputtering method with specific substrate temperature and oxygen proportion conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If transistor size is decreased to increase circuit integration, then device integration is improved, but electrical characteristics such as on-state current, off-state current, threshold, and subthreshold swing deteriorate
Solution Approach 1:
The patent introduces an electron trap layer with specific local properties (crystallized hafnium oxide with electron trapping capability) at the interface between the gate electrode and semiconductor layer. This localized functional layer adjusts the electrical characteristics specifically in the critical interface region without requiring overall transistor size increase, thus maintaining high integration while improving electrical performance.
Solution Approach 2:
The patent changes the physical and chemical parameters of the gate insulator by using crystallized hafnium oxide with specific crystal structure and electron trapping properties. By controlling the crystallization process and oxygen proportion during sputtering, the electron trap density and threshold voltage are adjusted, enabling fine-tuning of electrical characteristics in miniaturized transistors.
2Reliability
If threshold voltage is adjusted to improve electrical characteristics, then device performance is improved, but additional process steps and complexity are introduced
Solution Approach 1:
The patent combines the gate insulator formation step with the electron trap layer creation by using crystallized hafnium oxide that inherently provides both gate insulation and electron trapping functions. This merging of functions into a single layer eliminates the need for separate electron trap layer deposition and crystallization processes, reducing manufacturing complexity while achieving threshold voltage control.
Solution Approach 2:
The crystallized hafnium oxide layer serves multiple functions simultaneously: it acts as the gate insulator, provides electron trapping capability for threshold voltage adjustment, and offers high dielectric constant for effective gate control. This multi-functionality reduces the number of required layers and process steps while achieving multiple objectives.
3Loss of energy
If oxide semiconductor layer is used to achieve low leakage current, then power consumption is reduced, but carrier mobility and on-state current may be limited
Solution Approach 1:
The patent introduces a localized electron trap layer at the gate interface that specifically addresses the threshold voltage control issue without affecting the bulk properties of the oxide semiconductor channel. This localized intervention maintains the low leakage current characteristic of oxide semiconductors while enabling better on-state current through improved threshold voltage control.
Solution Approach 2:
The patent creates a composite structure combining oxide semiconductor layer with crystallized hafnium oxide gate insulator. The oxide semiconductor provides low leakage current while the crystallized hafnium oxide provides high dielectric constant and electron trapping capability, achieving both low power consumption and high on-state current through material composition optimization.
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 adjusts the threshold voltage, prevents deterioration of electrical characteristics, enhances integration, reduces power consumption, and ensures high reliability and data retention even when power is stopped, thereby improving the performance of semiconductor devices.
Implementation Method 1
manufactured using a sputtering method with specific substrate temperature and oxygen proportion conditions
Implementation Method 2
the electron trap layer includes electrons trapped by setting a potential of the gate electrode higher than a potential of the electrode
Data Source
AI summary
A semiconductor device in which the threshold is adjusted is provided. In a transistor including a semiconductor, a source or drain electrode electrically connected to the semiconductor, a gate electrode, and an electron trap layer between the gate electrode and the semiconductor, the electron trap layer includes crystallized hafnium oxide. The crystallized hafnium oxide is deposited by a sputtering method using hafnium oxide as a target. When the substrate temperature is Tsub (° C.) and the proportion of oxygen in an atmosphere is P (%) in the sputtering method, P≧45−0.15×Tsub is satisfied. The crystallized hafnium oxide has excellent electron trapping properties. By the trap of an appropriate number of electrons, the threshold of the semiconductor device can be adjusted.