Defects Induced by Carbon Contamination in Low-Temperature Epitaxial Silicon Films Grown with Monosilane

Abstract

The structures of the defects induced by carbon contamination in epitaxial silicon films grown with monosilane (SiH4) on silicon substrates were investigated. A new formation mechanism of defects associated with carbon in silicon epitaxial growth processes is proposed. The carbon contaminants were introduced prior to the growth by chemical vapor deposition (CVD), where the growth chamber was intentionally contaminated with organic materials. The carbon contaminant concentration was changed by adjusting the annealing conditions at temperatures ranging from 900°C to 1100°C. Silicon epitaxial films were grown by CVD at a temperature of 700°C. In this experiment, we found that pits were formed as dominant surface defects under the condition of a relatively low carbon concentration of less than 4.5×1013 cm-2, while mound defects were formed at a carbon concentration of more than 4.5×1013 cm-2. These defects can be explained by the formation of silicon carbide (SiC) islands resulting from the carbon contamination.

Growth of 28Si Quantum Well Layers for Qubits by a Hybrid MBE/CVD Technique

“…Besides, we observe that without pre-epitaxy atomic hydrogen irradiation at 700 °C, there are pits on the epitaxial layers without a difference in the XRD signal. These pits are similar to the pits described by Sato et al, 17 which can be originated from the carbon impurities on the substrate surface.…”

“…Hence, the surfaces are oxidized and also absorb organic contaminations. 15,16 If no proper substrate surface preparation is performed to remove the impurities, defects, such as pits, mounds, 17 and dislocations, 18 can be formed in the epitaxial layers and consequently affect the qubits' behavious. Atomic hydrogen irradiation is proposed to remove the carbon and oxygen impurities on the Si surface at relatively low temperatures as 700 °C.…”

Two-step cycling process alternating implantation and remote plasma etching for topographically selective etching: Application to Si3N4 spacer etching

“…48 This very small oxidation of the Si surface certainly occurred during the transfer from the HF treatment tool to the ARXPS analysis chamber. The presence of carbon contamination, that is considered to generate defects during epitaxial silicon film grown, 49 was not yet detected.…”

Preparation and tunneling magnetoresistance of (Ga,Mn)As trilayer structures on Si (0 0 1) substrates

“…However, residual contamination formed by oxide and carbon probably may remain on the Si surface because of the absence of high-temperature cleaning in the LT growth procedure [14]. The LT-GaAs deposited over contaminations could be crystallized initially by GaAs clustering during the deposition process and then by intermittent multi-annealing process.…”