SCREENING EFFECT ON THE ELECTRICAL BEHAVIOUR OF SILICON IN HF SOLUTIONS

Rabéa CHEGGOU, N. GABOUZE, A. KADOUNE

Résumé


Abstract:
The electrical behaviour of the P-Si in HF solutions of the modification of the silicon
electrolyte interface is studied. In this purpose, different deposits were realised (CHx, TiC and
porous film). Current-potential (I-V) characteristics of CHx coated electrodes in 5%HF and
TiC Coated electrodes under the same conditions, are shown similar to those obtained with
silicon [l,2].In both cases two current maxima are observed. The intensity of these peaks
decreases with increasing thikness of the CHx and Tic films becames resistive and screen
the electrochemical carriers transfer at the SI-HF interface [3]. The I-V characteristics of a
fresh electrode and an oxidized sample under the same conditions as previously described
were studied. It indicates that oxide layer at the Si surface becames resistive and blocks the
electrochemical carriers transfer at the SI-HF interface. The results of electrochemical
behavior of p-Si/TiC, p-SI/CHx and p-Si/porous silicon in HF solutions suggests that the
carriers transfer at Si/HF interface is affected by the thikness of the deposit films.

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