Harushige Kurokawa

Development of High-Throughput Batch-Type Epitaxial Reactor

Si/SiGe selective epitaxial growth is becoming a critical process step for ULSI fabrication on 65nm and beyond technologies with need for elevated source-drain or strained silicon channel to enhance device performance. This paper reviews the efforts to improve batch-type epitaxial reactors for high-volume device fabrication and shows recent progress in low-temperature Si/SiGe selective epitaxial process.

A Study on B Atomic Layer Formation for B-Doped Si1-xGex(100) Epitaxial Growth Using Ultraclean LPCVD System

Atomically controlled doping in heterostructure is a key technology to fabricate high-performance ultrasmall semiconductor devices. Atomic-layer doping of B and P in Si1-xGex epitaxial growth has been reported [1]. In the previous works, atomic layer formation of B on Si(100) and subsequent epitaxial growth of Si were investigated [2]. Recently, because the decomposition of BCl3 is rather gentle compared with B2H6, BCl3 is paid attention as a doping gas. In the present work, self-limited B atomic layer formation on Si1-xGex(100)(x=0-1) using BCl3 gas in an ultraclean low pressure CVD (LPCVD) was investigated. Si1-xGex epitaxial growth on Si(100) was performed at 450-500 C in a SiH4-GeH4 gas mixture using an ultraclean LPCVD reactor (Fig. 1), e.g. the strained 23 nm-thick Si0.7Ge0.3 film and the strain-free 200 nm-thick Ge film were prepared [3]. Formation of a B atomic layer on the substrates was performed by introduction of a BCl3-He-H2 or BCl3-He-Ar gas mixture. BCl3 exposure temperature dependence of B atom amount on Si1-xGex/Si(100) is shown in Fig. 2. It is found that B atom amount tends to increase with increasing