- The Features of Single-Crystal Thin Film
- Unique Features of KRYSTAL® Wafer's PZT Single-Crystal
- Types of PZT Thin Film KRYSTAL® Wafers
- Mechanism of Single-Crystal Deposition by KRYSTAL® Wafer
The most distinctive feature of our single crystal technologies is the broad process margin, which is made possible by unique buffer layer technologies.
The buffer layer changes its shape to fill in gaps between the substrate and the crystal lattice of the piezoelectric thin film, creating a single crystal structure with minimal residual stress.
Furthermore, advanced plasma control enables fine-tuning of material characteristics in keeping with the application, with no change in the material composition.
We offer single-crystal piezoelectric thin-film wafers (KRYSTAL® Wafer) for a variety of piezoelectric MEMS applications.
Piezoelectric materials manufactured using basic film structures have the following characteristics:
- They maintain continuous single crystal structures from the silicon (Si) substrate, and reflect single crystal structures without being influenced by the thickness of the piezoelectric thin film
- They have a “ Cube on Cube” structure; that is, a crystal structure somewhat like dice stacked up so they will not roll
- There are few crystal flaws in piezoelectric thin film on strontium ruthenate (SRO), enabling reliable operation even with sub-micron thickness.
These characteristics can be applied not only to PZT (lead zirconate titanate), which is well known as a piezoelectric material, but also to barium titanate (BTO) and numerous other materials as well. Silicon based substrates with a regular (100) orientation are used as a standard, but other orientations have the following characteristics:
- When the silicon substrate orientation of <(110) or (111)> is changed, the film orientation can be carried over from the upper layer, providing an optimum combination of materials.
We offer these platforms and proposes ideal combinations to meet the customers’ needs.
KRYSTAL® Wafer's single-crystal piezoelectric thin films shows superior electrical and mechanical characteristics compared to common poly-crystal piezoelectric thin films.
The most notable features of KRYSTAL® Wafer PZT thin film:
- Single crystal thin film
- Initial polarization from immediately after film forming is maintained
- High heat resistance, with no depolarization even at reflow temperatures (450℃)
- Dielectric constant is less than half compared to polycrystalline materials with similar displacement
Superior Electrical and Mechanical Characteristics
The piezoelectric property direction is aligned when single crystalized.
It exhibits superior actuator and sensor performance.
Single crystallization improves the bonding between atoms.
It has approx. 100 times longer life than polycrystal PZT.
By leveraging these unique features, KRYSTAL® Wafer offers two types of standard films with differing characteristics:
- Sensor specifications
These thin films have strong c-axis orientation, so the dielectric constant is reduced to 140 or less, which in turn increases the electric charge generated by distortion.
The films are designed to match applications using piezoelectric effects.
- Actuator specifications
These thin films have a high d-constant and withstand voltage, and a low dielectric constant.
The films are designed to match applications using inverse piezoelectric effects.
We can customize film characteristics using our superior plasma control. We provide customers with optimum PZT solutions based on their evaluation of these standard films.
We have successfully reproduced single-crystallization on customer equipment using KRYSTAL® Wafer.