Titanium Nitride Orientation Layer for Ferroelectric Memory
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Solution Overview
Problem
Existing methods for manufacturing ferroelectric memory devices face challenges in controlling the crystal orientation of layers within the ferroelectric capacitor, which affects the hysteresis characteristics and integration capabilities of these devices.
Innovation Solution
A method involving the formation of a titanium layer, a barrier layer with a specific crystal orientation, and subsequent heat treatment to convert the titanium layer into a titanium nitride layer, ensuring that the crystal orientation is reflected in subsequent electrode and ferroelectric layers, thereby enhancing the hysteresis characteristics and oxygen barrier capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a titanium layer is formed and directly converted to titanium nitride without forming a barrier layer first, then the manufacturing process is simpler, but the crystal orientation control of subsequent layers deteriorates
Solution Approach 1:
A barrier layer is formed on the titanium layer before the titanium layer is converted to titanium nitride. This preliminary formation of the barrier layer ensures that when the titanium layer is later nitrided, the barrier layer can reflect the crystal orientation of the titanium layer, thereby achieving good crystal orientation control in subsequent electrode and ferroelectric layers.
2Reliability
If the titanium layer is converted to titanium nitride before forming the barrier layer, then the oxygen barrier capability is improved, but the crystal orientation control of the barrier layer and subsequent layers deteriorates
Solution Approach 1:
The barrier layer is formed on the titanium layer before the titanium layer is converted to titanium nitride. This sequence ensures that the barrier layer can reflect the crystal orientation of the titanium layer, achieving good crystal orientation control while maintaining oxygen barrier capability through the subsequent titanium nitride layer.
3Device complexity
If the crystal orientation of layers in the ferroelectric capacitor is not well controlled, then the manufacturing process is less complex, but the hysteresis characteristics and integration capabilities deteriorate
Solution Approach 1:
A barrier layer is formed on the titanium layer before nitridation to enable crystal orientation reflection. This preliminary action ensures that the titanium layer's crystal orientation is reflected in the barrier layer, which in turn enables good crystal orientation control in subsequent electrode and ferroelectric layers, achieving excellent hysteresis characteristics and integration capabilities.
4Manufacturing precision
If a barrier layer with excellent crystal orientation is formed by forming it on a titanium layer before nitridation, then the crystal orientation control is improved, but the manufacturing steps increase
Solution Approach 1:
The barrier layer is formed on the titanium layer, and then the titanium layer is converted to titanium nitride through nitridation. These steps are combined in a specific sequence where the barrier layer formation on the titanium layer serves dual purposes: providing oxygen barrier capability and enabling crystal orientation reflection, thereby achieving good crystal orientation control without excessively increasing manufacturing complexity.
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
This approach allows for the precise control of crystal orientation in ferroelectric layers, resulting in semiconductor devices with improved hysteresis characteristics and enhanced integration capabilities, even in miniaturized forms, while preventing oxidation of underlying layers.
Implementation Method 1
changing the titanium layer to a titanium nitride layer by conducting a heat treatment in an atmosphere including nitrogen
Implementation Method 2
in a later step to be conducted (for example, in recovery anneal (i.e., a heat treatment in an oxygen atmosphere) to recover the characteristics of the ferroelectric layer), the titanium layer is oxidized, and a plug in an underlying layer can be prevented from being oxidized
Data Source
AI summary
A method for manufacturing a semiconductor device, the method including the steps of: (a) forming a titanium layer above a substrate; (b) forming a barrier layer above the titanium layer; (c) changing the titanium layer to a titanium nitride layer by conducting a heat treatment in a nitrogen containing atmosphere; (d) forming a first electrode above the barrier layer; (e) forming a ferroelectric layer above the first electrode; and (f) forming a second electrode above the ferroelectric layer.