Electrical damage to silicon devices due to reactive ion etching

The damage, due to reactive ion etching in CF₄+O₂ plasma, has been investigated by I-V and C-V techniques using silicon devices such as Au/n-Si Schottky contacts, p⁺-n diodes and MOS structures. The forward characteristics of a Schottky diode and an exposed junction diode are significantly degraded due to RIE. The amount of damage increases with increasing RF voltage. Considerable recovery occurred when various post RIE treatments were used for the lower RF voltage RIE etching. Almost no recovery upon annealing is found for the higher voltage etching, which suggests the formation of more complex, defect sites at the higher etching voltages. MOS capacitors as well as MOSFETS were used to investigate the damage effects of RIE in Si-SiO₂ systems.