ISSN:
1089-7550
Source:
AIP Digital Archive
Topics:
Physics
Notes:
Silicon oxide, SiOx (1≤x≤2), formed by molecular-beam deposition (MBD) has many attractive optical, electrical, mechanical, and chemical properties which make it a suitable dielectric for many semiconductor device applications. It can be thermally evaporated at a much lower temperature than Si, SiO2, or Si3N4 and it condenses on cooler surfaces in uniform and adherent stoichiometric SiO (x=1) films when evaporated in high vacuum. At low deposition rates and at high pressures of oxygen, SiOx (1≤x≤2) films result. This allows variation of refractive index, stress, and other properties with x. MBD-SiOx films are insensitive to moisture absorption. A high quality thin film of SiO2 formed on the surface of SiOx, when exposed to an oxidizing ambient, protects the SiOx film underneath from the environment. Dielectric breakdown strength of the SiO films is comparable to that of other high quality deposited dielectrics. In general, the SiO (x=1) films are under tensile stress of 〈100 MPa, which is significantly lower than that observed in other dielectric films. Introduction of a small amount of oxygen during deposition reduces the tensile stress; at an O2 pressure of 5×10−7 Torr and above, the films are in compression. This allows the tunability of stress, and deposition of films essentially free from stress. Furthermore, both Si and SiO have similar values of the linear thermal expansion coefficients (average values between 23 and 350 °C: 3.37×10−6 and 2.7×10−6 °C−1, respectively). As a result, SiOx/Si films develop little stress during thermal cycling. © 1995 American Institute of Physics.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1063/1.360024
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