Electrical characteristics of metal-Al2O3-Si structure deposited by ICBE technique for application of semiconductor device fabrication

We have deposited Al₂O₃ films by Ionized Cluster Beam Epitaxy (ICBE) technique at low substrate temperature (100~500°C). In this paper, the details of the film deposition system and fundamental characteristics of the Al-Al₂O₃ -Si structure were described and the dielectric breakdown of Al ₂O₃ was studied. Aluminum oxide (Al₂O ₃) offers some unique advantages over the conventional silicon dioxide (SiO₂) gate insulator; greater resistance to ionic motion, better radiation hardness and higher possibility of obtaining low threshold voltage in MOSFETs and use as gate insulator in nonvolatile memory devices. We have undertaken a study of the dielectric breakdown of Al₂O₃ on Si deposited by ICBE technique. In our experiments, we have altered the Al₂O₃ thickness from 300 to 1400 Å. The resistivity of Al₂ O₃ films varies from 10⁸ Ω-cm for films less than 100 Å to 10¹³ Ω-cm for films on the order of 1000 Å. The flat band shift is positive, indicating negative charging of oxide. The magnitude of the flat band shift is less for negative bias than for positive bias. The relative dielectric constant was 8.5~10.5 and the electric breakdown fields were 6~7 MV/cm (+bias) and 11~12 MV/cm (-bias). The average fields required to produce breakdown in 10³ sec were approximately 4.5 MV/cm for positive bias on either Al or Au field plates, 5.0 MV/cm for negative bias on Al and 6.5 MV/cm for negative bias on Au