Abstract

As integrated-circuit device dimensions decrease, the importance of having new reliable processes for growing MOS gate oxides becomes more and more evident. Short process times and low process temperatures are desirable features in view of tight thermal budget constraints and the need for precise location of dopants. However, conventional thermal oxidation to grow high quality films usually requires relatively long oxidation times and relatively high temperature. Previous research on negative point (anodic) corona-processed SiO 2 films has shown that the thermal budget incurred using the corona process is much lower than in standard thermal oxidation due to the greatly enhanced oxidation rate. Promising results of low-T corona-processed [Special characters omitted.] 100Å films have shown that the films had physical characteristics comparable to those obtained in thermal oxidation. This research extends the previous work: (a) thin oxides ([Special characters omitted.] 200Å) are processed in order to be potentially more relevant to modern MOS processes, and (b) a more thorough electrical characterization is initiated. Electrical tests show that oxide and interface charges are comparable to thermal oxides. Breakdown characteristics are promising. The boundary between the corona-processed and control regions is found to be severely compromised. Subsequent corona treatments which overlap such boundary regions are found to restore the quality of the oxide. Fourier Transform Infrared (FTIR) Spectroscopy results show that the negative corona films have a different structure from that of thermal oxide films. Electrical tests on positive point (cathodic) corona-processed SiO 2 films show that the electrical quality of the films is much worse than that of standard thermally grown films, grown at a similar temperature. In the interests of growing more-uniform negative-corona SiO 2 films on broader areas of silicon wafers, experiments using multi-point or multi-needle structures were conducted. The enhancement profiles of films grown in both positive and negative cases are simulated using linear-parabolic rate constants, modified to account for the corona current