Novel InGaAs contact layer growth for hetero-junction bipolar transistors (HBTs) by using the multiple group-V source molecular beam epitaxy (MBE) system

• Published in: Journal of crystal growth 1999-05, Vol.203 (1), p.18-24
• Main Authors: Kadoiwa, Kaoru, Izumi, Shigekazu, Yamamoto, Yoshitsugu, Hayafuji, Norio, Sonoda, Takuji
• Format: Article
• Language: English
• Subjects: Applied sciences; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Contact resistance, contact potential; Cross-disciplinary physics: materials science; rheology; Deposition technology; Electronic structure and electrical properties of surfaces, interfaces, thin films and low-dimensional structures; Electronic transport in interface structures; Electronics; Exact sciences and technology; Group-V sources; Hetero-junction bipolar transistor; InGaAs; Materials science; MBE system; Methods of deposition of films and coatings; film growth and epitaxy; Microelectronic fabrication (materials and surfaces technology); Molecular, atomic, ion, and chemical beam epitaxy; Physics; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices
• ISSN: 0022-0248; 1873-5002
• DOI: 10.1016/S0022-0248(99)00056-1

Dependence of layer surface morphology and electrical properties on growth conditions, growth temperature and supplying conditions of group-V sources such as solid-As and AsH 3 hydride gas, has been investigated with specially designed MBE system, including both solid-As source cell and gas source cracking cell, for highly lattice-mismatched (+4%) In 0.5Ga 0.5As layer grown on GaAs. We demonstrate that utilizing of AsH 3 hydride source enables us to obtain a superior smooth surface in comparison with utilizing solid-As source. The HAZE level for the former source is reduced to one twentieth of the latter. The advantage of gas-source MBE (GS-MBE) method (hydrogen effect) was realized as suppressing In segregation. The effective hydrogen comes from AsH 3 hydride that acts as the surfactant that controls coherent small 3D islands formation during initial growth stage. The optimized GS-MBE growth method, under AsH 3 flow rate of 3 SCCM and growth temperature of 470°C, establishes that the In x Ga 1− x As ( x=0.6) layer grown on GaAs with the surface is as smooth as the surface of GaAs substrate, and also shows the contact resistance to be 4×10 −8 Ω cm 2. This value is well-fitted for nonalloy ohmic contact by using W/Si as emitter electrodes for HBTs.