Anodic Formation of Oxide Films on Silicon

Abstract

Dense oxide films have been formed anodically on p-and n-type singlecrystal Si in connection with the electrical properties of Si surfaces. Concentrated HNO~ or H~PO~ permit forming, but the highest voltage obtainable is less than 200 v. A solution of KNO~ in N-methylacetamide permits forming to 560 v, and is also preferable in other respects.The field during forming is of the order 2.6 • 10 ~ v/cm corresponding to a thickness increment of about 3.8A/v. The ratio has been found as well from interference colors and direct weighing, as by capacitance measurements. Above an oxide thickness of 400A the rate-limiting step for film growth is inside the oxide.The ionic current efficiency of film growth is very low. In methylacetamide it can be increased by addition, for example, of chloride ions or more so by fluoride ions. The oxide is an electrolytic rectifier and behaves similar to an oxide on A1 or Ta. The direction of easy flow for electrons is from the Si to the electrolyte.

Anodic oxide films on silicon carbide

“…A break-down occurs at electric field intensity Е ~2. 10 6 V/m in the oxide, which is substantially lower than the intensity of the field needed for collision ionization. In a number of experiments an effect of "autoelimination" of the thermal break-down was observed: the electrode evaporated in the area of the break-down, thus preventing AOFs destruction.…”

“…Acid concentration varied between 5 % and 30 %. As it is well known, the kinetics of SiC anodic oxidation is similar to that of silicon (Si) [1,3,10,11]. The growth of AOFs is related to the diffusion of two types of ions: oxygen-containing anions from the electrolyte to the growing oxide, and cations of the substrate to the oxideelectrolyte interface.…”

Surface-Functionalized Porous Silicon Wafers: Synthesis and Applications

“…Early works on electrochemical treatment of silicon surfaces dealt with problems of anodic oxidation, electropolishing and chemical etching as early as 1937 (Güntherschulze & Betz, 1937). A more detailed study was performed twenty years later (Schmidt & Michel, 1957). The first mention of PS material (without being named in that way) was reported in 1956, when A. Uhlir Jr. found unusual deposits on anodized silicon samples (Uhlir, 1956).…”

Contribución al estudio del comportamiento de silicio poroso nano-estructurado en fluidos corporales simulados para el desarrollo de nuevos materiales biocompatibles y biodegradables.

“…Después de este tipo de tratamientos las muestras son mucho más estables frente a la oxidación ambiental [221][222]. El proceso de derivatización se puede realizar modificando las muestras por fisisorción [223], en este caso las terminaciones hidrofóbicas Si-H x se mantienen, se utiliza para ello un surfactante que se orientará con la parte hidrofóbica hacia el silicio y con la parte hidrofílica hacia el agua (que es el disolvente en el FCS).…”

“…[221][222][223][224][225]. En cualquier caso el rendimiento es siempre bastante bajo, por ejemplo, en el caso de las inducidas por radiación es de alrededor de un 14%.…”