Enabling Ultra-High Resolution, Low Power Displays
Display devices that require higher resolution are typically greater than 300 pixels-per-inch and call for a change at the transistor level to a higher mobility material. Click here to learn more about current smartphone resolution and where it's headed. In order to accommodate more pixels for higher resolution, traditional amorphous silicon (a-Si)-based transistors can be made smaller but have to compensate by using more power to maintain picture quality ultimately leaving less power dedicated to battery life. I can't think of anyone on the planet who wants to sacrifice battery life. Fortunately, we have a solution! Metal oxide (MoX) and low temperature polysilicon (LTPS) -based transistors can scale down the transistor size using low power while meeting the higher mobility requirements that consumers demand in the latest mobility gadgets.
Amorphous metal oxide thin film transistors (TFTs) are now available for some high resolution and low power mobile applications. In the near future, MO TFTs will also power tablet PCs with resolution over 250 pixels per inch as well as 4K TVs and 3D TVs. Later adoption will include some smartphones and this technology will eventually be applied to OLED flexible displays.
This week Applied Materials announced three new products to enable customers to bring metal oxide-based TFT displays to the marketplace and power the high resolution displays of tomorrow.
Today's challenges in manufacturing metal oxide-based TFTs include device stability, mura (an anomaly in the picture quality visible to the eye) and yield. Metal oxide TFTs include both a PVD process for the IGZO active layer which requires precise IGZO uniformity to prevent mura and low particles; as well as a PECVD-based SiOx gate insulator with low hydrogen to promote device stability and protection against IGZO degradation when exposed to hydrogen.
The Applied AKT 55KS PECVD system for gen 8.5 metal oxide applications optimizes SiOx processes for uniformity and particle defect reduction in order to produce superior PECVD films for metal oxide-based transistors. The metal oxide TFT requires low defect and hydrogen-free silicon oxide dielectric material. The contact between active IGZO later and gate insulator is key to a stable TFT and requires a low defect hydrogen free interface.
The Applied AKT-PiVot® 25K DT dual track system is offered for Generation 6 substrates and the AKT PiVot 55K DT for generation 8.5 substrates. The systems offer the PiVot PVD tool's superior static chamber deposition with a new dual track capability for manufacturing flexibility. The dual track single chamber design reduces the overall footprint of the system while allowing for increased throughput with two independent tracks for IGZO deposition capability. The rotary target array for the PiVot DT allows for uniform gas distribution, and fewer particles from material redeposition and module formation, resulting in less defects and a mura-free IGZO active layer for metal oxide TFT backplanes.
Click here to access the press release with more information about today's product launches.