Alternatives to thick MBE-grown relaxed SiGe buffers

• Published in: Thin solid films 2000-07, Vol.369 (1-2), p.148-151
• Main Authors: HACKBARTH, T, HERZOG, H.-J, ZEUNER, M, HÖCK, G, FITZGERALD, E. A, BULSARA, M, ROSENBLAD, C, VON KÄNEL, H
• Format: Article
• Language: English
• Subjects: Applied sciences; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Deposition technology; Electronic structure and electrical properties of surfaces, interfaces, thin films and low-dimensional structures; Electronic transport phenomena in thin films and low-dimensional structures; Electronics; Exact sciences and technology; Low-dimensional structures (superlattices, quantum well structures, multilayers): structure, and nonelectronic properties; Low-field transport and mobility; piezoresistance; Microelectronic fabrication (materials and surfaces technology); Physics; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties)
• ISSN: 0040-6090; 1879-2731
• DOI: 10.1016/S0040-6090(00)00795-1

We have investigated several growth concepts for strain relieved SiGe buffers as basis for high frequency transistors. Modulation doped quantum wells (MODQWs) were realized by molecular beam epitaxy (MBE) on top of thick graded buffers prepared by MBE, ultra-high vacuum chemical vapor deposition (UHVCVD) and low-energy plasma-enhanced CVD (LEPECVD). Additionally, thin buffers including a specific layer grown at low temperature (LT) were realized entirely by MBE. The overgrown thick CVD samples show comparable transport properties and thermal stabilities to those on thick graded MBE buffers. Mobilities of up to 90 000 cm super(2)/V s have been measured at 30 K. Thin LT-MBE structures show slightly worse properties but are superior to conventional constant composition buffers.