Hot-wall batch-type CVD tool for high-k (Ba,Sr)TiO3 capacitors

A hot-wall batch type BST-CVD tool with fast thermal processing (FTP) furnace and individual vaporizing liquid source supply system (ILSS) was developed for uniform deposition of BST. We also employed an in-situ multi-step (IMS) process that is sequential repetition of thin amorphous BST deposition and its crystallization in the same reactor to reconcile conformal BST deposition and good electrical performances. BST deposited by our hot-wall CVD shows slight substrate dependence (metal coated or not), therefore hotwall CVD is superior to a single slice tool for reduction of test wafer running. IMS deposited BST shows almost 100% step coverage, lower carbon impurity concentration than single step deposited BST and sufficient electrical characteristics (leakage current <10^-7 A/cm², Teq<0.5 nm) for both SRO and Ru electrodes.