Low-rate plasma oxidation of Si in a dilute oxygen/helium plasma for low-temperature gate quality Si/SiO₂ interfaces

Low-rate plasma oxidation of Si, involving a small oxygen concentration in a low-power He plasma at low processing temperatures (∼350°C), is shown capable of producing excellent interface properties, good uniformity, and low defect density. As an interfacial layer for plasma-enhanced chemical vapor deposited (PECVD) SiO2 films, the plasma oxide is key to achieving high quality composite (plasma oxide/PECVD) oxide structures, which essentially match the electrical quality of thermal oxides. Such low-temperature oxide films are suitable for critical device applications, such as the gate oxide in metal-oxide-semiconductor devices and the base passivation layer in advanced bipolar devices.