Phase-change memory adhesion via TiN-TiOx composite and recessed contacts
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional phase-change random access memory devices experience poor adhesion between metal contacts and diodes, leading to inclined diode patterns during etching and cleaning processes due to degradation of the titanium nitride ohmic contact layer, affecting the reliability of the memory device.
Innovation Solution
The formation of recesses in the ohmic contact layer using titanium nitride (TiN) and the strategic placement of diodes at uniform distances to enhance adhesion and prevent pattern inclining, along with the use of interlayer dielectric layers to support diodes and maintain consistent critical dimensions between memory cells.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If titanium nitride (TiN) is used as the ohmic contact layer to improve adhesion between metal contacts and diodes, then adhesion force is improved, but the TiN layer degrades in subsequent annealing processes causing interface problems and diode pattern inclining
Solution Approach 1:
The patent introduces a composite structure consisting of two distinct layers: a lower adhesion layer made of titanium nitride (TiN) that provides strong bonding between metal contacts and diodes, and an upper barrier layer made of titanium oxide (TiOx) that protects the TiN layer from degradation during annealing processes. This composite material approach resolves the contradiction by combining materials with complementary properties - the TiN layer addresses the adhesion requirement while the TiOx layer addresses the stability requirement, allowing both functions to coexist without interference
2Ease of manufacture
If the ohmic contact layer is formed without recesses to simplify manufacturing, then manufacturing complexity is reduced, but diode patterns incline during etching and cleaning processes
Solution Approach 1:
The patent applies preliminary action by forming recesses in the ohmic contact layer before depositing the diode material. These pre-formed recesses serve as structural guides that constrain the diode patterns during subsequent etching and cleaning processes, preventing them from inclining. The recesses are created through a controlled etching process that removes material to form凹陷 structures, which then act as physical boundaries for pattern formation, ensuring precise alignment without requiring complex manufacturing steps later
Data Source
AI summary
A phase-change random access memory device includes a semiconductor substrate, an interlayer dielectric layer formed over the semiconductor substrate and having contact holes defined therein, metal contacts formed in the contact holes, an ohmic contact layer formed over the metal contacts and having recesses defined therein, and switching elements formed over the recesses of the ohmic contact layer.