Silicon/Electrolyte Interface - Electrochemistry of Silicon and Its Oxide - page 86

concentration. Also, when there is little etching of the materials, no significant
difference exists between p and n types. On the other hand, an appreciable potential
difference exists between n and p types in solutions in which the etch rate is high.

Dissolved oxygen in solutions can strongly affect OCP of silicon electrodes.
Bertagna et al . 146,522 found that OCP of both p- Si and n- Si in 5% HF solution shifts to
more positive values, by 100-150 mV, in oxygenated solution as shown in Table
146,968 The effect of oxygen can readily be explained by the change involved in the
anodic and cathodic reactions described in Fig. 1.26. An increased total cathodic reac-
tion rate due to the oxygen reduction results in a shift of the cathodic curve from

2.17.

to

and thus changes OCP from to