In this paper a systematic investigation of nitrided oxides obtained by Rapid Thermal Oxidation/Nitridation (RTO/RTN) in AMAT Centura System is reported. Two different aspects were considered: first the comparison between single wafers and batch technology, second the different possible oxide architecture achievable with RTO/RTN system (i.e. RTO + RTN, RTN + RTO, RTN + RTO + RTN). Both morphological and patterned wafers were processed. Physical and chemical characterizations were carried out by means of SIMS, XPS, ELYMAT, AFM and Etching Rate studies. Morphological results were then correlated to electrical data obtained on MOS capacitors. The film obtained performing a NO RTN nitridation of the native oxide followed by a ISSG (In Situ Steam Generation) oxidation exhibited very promising electrical properties that made it an appealing candidate as gate dielectric in CMOS and Flash memories applications.

In this paper a systematic investigation of nitrided oxides obtained by Rapid Thermal Oxidation/Nitridation (RTO/RTN) in AMAT Centura System is reported. Two different aspects were considered: first the comparison between single wafers and batch technology, second the different possible oxide architecture achievable with RTO/RTN system (i.e. RTO + RTN, RTN + RTO, RTN + RTO + RTN). Both morphological and patterned wafers were processed. Physical and chemical characterizations were carried out by means of SIMS, XPS, ELYMAT, AFM and Etching Rate studies. Morphological results were then correlated to electrical data obtained on MOS capacitors. The film obtained performing a NO RTN nitridation of the native oxide followed by a ISSG (In Situ Steam Generation) oxidation exhibited very promising electrical properties that made it an appealing candidate as gate dielectric in CMOS and Flash memories applications.

A newly-developed technique for the simultaneos characterization of the oxide-silicon interface properties and of bulk impurities was used for a systematic study of the nitridation process of thin oxides. This technique is based upon surface recombination velocity measurements, and does not require the formation of a capacitor structure, so it is very suitable for the characterization of as-grown interfaces. Oxides grown both in dry and in wet enviroments were considered, and nitridation processes in N 2 O and in NO were compared to N 2 annealing processes. The effect of nitridation temperature and duration were also studied, and RTO/RTN processes were compared to conventional furnace nitridation processes. Surface recombination velocity was correlated with nitrogen concentration at the oxide-silicon interface obtained by Secondary Ion Mass Spectroscopy (SIMS) measurements. Surface recombination velocity (hence surface state density) decreases with increasing nitrogen pile-up at the oxide-silicon interface, indicating that in nitrided interfaces surface state density is limited by nitridation. NO treatments are much more effective than N 2 O treatments in the formation of a nitrogen-rich interface layer and, as a consequence, in surface state reduction. Surface state density was measured in fully processed wafers before and after constant current stress. After a complete device process surface states are annealed out by hydrogen passivation, however they are reactivated by the electrical stress, and surface state results after stress were compared with data of surface recombination velocity in as-processed wafers.

In this paper, we report the study of rapid thermal oxidation of silicon in N2O ambient using the Applied Materials RTP Centura rapid thermal processor, and N2O oxide thickness and compositional uniformities with respect to gas flow rate and wafer rotation speed as well as other process parameters. It was found that N2O oxide uniformity is strongly dependent on gas flow rate and wafer rotation speed in addition to process pressure. With optimized setting of the process parameters, excellent oxidation uniformities (one sigma < 1%) were obtained at atmospheric pressure N2O ambient. Nitrogen concentrations of such uniform oxides grown at 1050°C atmospheric pressure N2O oxidation processes were 1.7% for a 40 Å oxide and 2.5% for a 60Å oxide, respectively, as characterized by SIMS analysis.

Nitric oxide rapid thermal nitridation of thin gate oxides was investigated. Oxides from 25 to 55 Å were grown in O 2 and subsequently nitrided in a nitric oxide (NO) ambient using an Applied Materials RTP Centura chamber. Nitrogen incorporation and film thickness growth during NO nitridation were evaluated. Peak nitrogen incorporation was most strongly influenced by temperature and time, with moderate influence by initial oxide thickness, and no significant influence due to NO flow rate. Peak nitrogen concentrations ranged from 1 to 9 atomic percent as characterized by Secondary Ion Mass Spectrometry (SIMS) analysis. Oxide growth during nitridation ranged from 2 Å to 11 Å with no degradation in uniformity. These data were used in the design of two 40 Å oxynitride processes incorporating 2 and 4 peak atomic percent nitrogen. High quality MOS capacitors were demonstrated with these dielectrics. Performance was compared against a baseline furnace process as well as non-nitrided RTO. Throughout this work, the chamber integrity was monitored using visual inspection, minority carrier lifetime (MCLT) and surface photovoltage (SPV). No contamination, corrosion or other degradation of the process chamber was observed in over 6 months’ operation with over 700 NO processes completed. The controllability, uniformity and high nitrogen incorporation of rapid thermal NO nitridation make it an attractive process for deep sub-micron gate insulators.