Evaluation of Surface Damage on Silicon Induced by Reactive Ion Etching Using Current-Voltage Characteristics.

Reactive ion etching (RIE) creates a damaged layer at the surface of the etched material and changes the electrical characteristics of the surface. The degree of the damage has been evaluated from the current-voltage (I-V) characteristics of the Schottky diode fabricated on the damaged surface. To evaluate the depth distribution of the damage, the damaged surface was etched gradually using chemical dry etching (CDE), a Low-damage dry etching method. Each time the surface was etched, the I-V characteristics of the diode fabricated on the surface were measured. Assuming that RIE generates impurities or crystal defects (together with the damage defects) which act as donors at the silicon surface, the concentration and depth distribution of the damages have been obtained from the saturation current density of each I-V characteristic. As a result, damage defects of 1 × 1019 cm-3 have been found at the surface, and the depth of the damage is approximately 15 to 20 nm front the surface. [ABSTRACT FROM AUTHOR]