Characterization of In Situ P-Type and N-Type Doped Si and GeXSi1−X Films Grown by Low Temperature Remote Plasma Chemical Vapor Deposition

Abstract

ABSTRACTLow temperature Si and Si1−xGex epitaxy is one of the major thrusts in the trend towards low temperature Si processing for future generation ULSI circuits and novel Si-based devices. A remote plasma-enhanced chemical vapor deposition (RPCVD) technique has been developed to achieve Si homoepitaxy and Si1−xGex heteroepitaxy at low temperatures (≤450'C). P-type films have been grown by introducing 90 ppm or 5000 ppm B2H6/He into the system during the growth process to achieve in situ electrically active boron doping. A mesa diode structure with minimal thermal budget in the fabrication process has been employed to evaluate the properties of the boron-doped Si and Si1−xGex films grown at 450°C by RPCVD. Leakage current densities are reduced for diodes grown at 14–18 W (40–50 Å/min. growth rates) compared to similar devices grown at 6.6 W (5 Å/min.). N-type films have been grown by the introduction of 50 ppm PH3/He. Secondary ion mass spectroscopy (SIMS) has been employed to analyze the boron and phosphorus incorporation efficiencies and doping profiles under different conditions. Boron and phosphorus doping profile transitions as sharp as 50–100 Å/decade have been achieved. Transmission electron microscopy (TEM) has been used to investigate the microstructure of the B-doped films.