Novel Precursor for Alkaline Earth Metal-Containing Film Deposition (18-Jan-2010)

Disclosed herein are non-limiting embodiments of compositions, methods and apparatus used for the manufacture semiconductor, photovoltaic, LCF-TFT, or flat panel type devices.

Background

Ultra-thin, high dielectric constant films, “high-k”, that can maintain discrete interfaces and amorphous structure during high temperature fabrication processes are critical to future minimization of micro-electronic devices.  In particular, there is considerable need to identify replacement dielectric films for the gate oxide insulator in Complementary Metal Oxide Semiconductor transistors and the capacitive charge storage in Dynamic Random Access Memory (DRAM) cells. For decades, silicon dioxide (SiO₂) was a reliable dielectric, but as transistors have continued to shrink and the technology moved from “Full Si” transistor to “Metal Gate/High-k” transistors, the reliability of the SiO₂-based gate dielectric is reaching its physical limits

In order to maintain thickness control at the needed dimensions of nanometers within the gate oxide and to provide sufficient conformal coverage down the deep trenches of DRAM devices, atomic layer deposition (ALD) has been identified as the preferred technique over other techniques like e-beam deposition, physical vapor deposition, and chemical vapor deposition.

There are a number of high-κ materials that would seem suitable for these applications, but the attempt to implement most of these materials into the manufacturing process has unraveled numerous problems. Some of the more critical issues are interface stability, morphology stability, and process integration new generation of oxides based on alkaline earth metal such as STO, SRO, SrTa₂O₆, SrBi₂Ta₂O₉, BST, BSR, calcium praseodymium manganese oxide and derivatives are thought to give significant advantages in capacitance compared to conventional dielectric materials.

Nevertheless, deposition of alkaline earth metal-containing layers is difficult and new material and processes are more and more needed. For instance, atomic layer deposition, ALD, has been identified as an important thin film growth technique for microelectronics manufacturing, relying on sequential and saturating surface reactions of alternatively applied precursors, separated by inert gas purging. The surface-controlled nature of ALD enables the growth of thin films of high conformality and uniformity with an accurate thickness control. Unfortunately, the successful integration compounds used for depositions into vapor deposition processes has proven to be difficult.

As well as for ALD, new CVD processes are also required for rare earth metal materials. Other sources and methods of incorporating rare earth metal materials are being sought for new generations...