Effect on rapid thermal oxidation process on electrical properties of porous silicon

Abstract EN

In this work, the porous silicon was prepared by using stain etching in HF-HNO3 at different etching times.

Then Rapid Thermal Oxidation (RTO) processes were used for surface treatment at different temperature and oxidation time to enhancement sample properties.

Fourier Transforms infrared (FTIR) spectrum exhibit the formation of SiHx (x = 1, 2) and Si-O bonds which indicate the present of porous structure and formation of oxidation porous layer.

The Capacitance – Voltage characteristics reveal that effective carrier density is 36 * 1015 cm-3 for sample etching time at 2min, while there was a change from (37.8 * 1015 to 45.7 * 1015) cm-3 for sample oxidation at different oxidation temperature (373–973) K and from (38.2 * 1015 to 40 * 1015) cm-3 for sample oxidation at different oxidation time (0.5–3.5) min.

Also the porosity was (45.56 %) for PS / p-Si etching at 2min while reduce from (45 % to 35.4 %) with oxidation temperature, and from (44.2 % to 40.5 %) with oxidation time.

From photocurrent characterized, that the photosensitivity for PS / p-Si structure is better where etching time at 2min, and its 0.2545 A/W at 370nm, and it increased after Rapid Thermal Oxidation (RTO) from (0.34 to 0.44) A / W with different oxidation temperature, and changed from (0.35 to 0.34) A / W with different oxidation time, so that sandwich hetrojunction exhibit good efficiency photodiode.