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Posted: December 9, 2008
Viable CVD Phase Change Material Deposition for Sub-40 Nanometers Structures
(Nanowerk News) ATMI, Inc. and Ovonyx, Inc., today announced that the companies successfully demonstrated Germanium Antimony Telluride (GST) -based Phase Change Memory (PCM) devices made with Chemical Vapor Deposition (CVD) processes. These methods were scalable to sub-40 nanometers (nm), high aspect ratio, high density, and three-dimensional structures. PCM devices built with the CVD processes demonstrated endurance exceeding 10(6) write-erase cycles.
PCM devices incorporating GST materials are commercially available today, and are generally produced using traditional physical vapor deposition techniques. Working with optimized GST precursor materials from ATMI and phase change technologies from Ovonyx, the companies have now deposited GST films using more scalable CVD processes. It enables deposition into small, 3-D features and results in functional phase change devices of the size, speed, and endurance (able to operate over a million cycles without degrading) that will allow smaller cell size and more scalable application in upcoming high-performance Flash and DRAM applications.
"Today's forms of memory are fast approaching their physical limits in speed and density," said Tod Higinbotham, ATMI Executive Vice President, Process Solutions. "The ability to apply a high-volume process like CVD to this challenge enables future generation phase change memory products with greater scalability and lower cost. The strength of Ovonyx's expertise in PCM developments and the results of a collaboration announced only last March have already cracked the door open to commercial steps for this CVD approach to PCM technology."
Using ATMI's GST precursor materials, the companies achieved excellent amorphous film morphology in sub-40 nm contact-like structures with aspect ratios of up to 5:1. The ability to use CVD processing allowed Ovonyx and ATMI to deposit the GST material into the 3-D, high aspect ratio structures, which permits implementation of the highly scalable "confined cell" PCM technology. Confined cell allows fast write-times and high density packing of bits, thereby making PCM increasingly competitive compared with Flash and DRAM. The CVD-deposited GST films exhibited phase change functions with an endurance exceeding 10(6) cycles, exceeding typical flash write-erase cycle specifications.
"ATMI has supplied chemicals and process solutions to a number of leading research projects on GST-based phase change memory," said Chuck Dennison, Chief Operating Officer of Ovonyx. "Capitalizing on ATMI's experience and enabling conformal deposition processes like CVD have resulted in significant progress in efforts to demonstrate high performance CVD deposited phase change memory and to define a scalable and efficient path to future PCM products."
Ovonyx's PCM technology is an emerging non-volatile memory with expected scalability down to sub-10 nm dimensions. CVD based confined-cell technology allows the increased scaling and cost-reduction required to pursue next-generation products. ATMI's new GST precursors enable the use of mature CVD technologies for deposition into small, high aspect ratio structures consistent with confined cells.
About Ovonyx, Inc.
Ovonyx was formed with the charter to commercialize its proprietary phase-change semiconductor memory technology originally invented at Energy Conversion Devices, Inc. Ovonyx nonvolatile PCM technology offers significantly faster write and erase speeds through its capability for byte-write in either direction (avoiding the need to erase a block to write a bit), higher cycling endurance, and better scaling performance with new generations of photolithography than conventional Flash memory. Relative to DRAM, PCM eliminates the refresh power by retaining its memory without power. PCM also has the advantage of a simple fabrication process that allows the design of semiconductor chips with embedded nonvolatile memory using only a few additional mask steps. Ovonyx is pursuing commercialization of its array-addressed memory systems through licenses and joint development programs with semiconductor manufacturers including BAE Systems, Intel Corporation, ST Microelectronics, Elpida Memory, Samsung Electronics, Qimonda AG, and Hynix Semiconductor Inc. For more information, please visit www.ovonyx.com.
About ATMI, Inc.
ATMI provides specialty materials and high-purity materials handling and delivery solutions to the worldwide semiconductor industry. For more information, please visit http://www.atmi.com.