Etching Rate of Silicon Dioxide Using Chlorine Trifluoride Gas

Abstract

The etching rate behavior of silicon dioxide (SiO 2 , fused silica) using chlorine trifluoride (ClF 3 ) gas is studied at substrate temperatures between 573 and 1273 K at atmospheric pressure in a horizontal cold-wall reactor. The etching rate increases with the ClF 3 gas concentration, and the overall reaction is recognized to be of the first order. The change of the etching rate with increasing substrate temperature is nonlinear, and the etching rate tends to approach a constant value at temperatures exceeding 1173 K. The overall rate constant is estimated by numerical calculation, taking into account the transport phenomena in the reactor, including the chemical reaction at the substrate surface. The activation energy obtained in this study is 45.8 kJ mol À1 , and the rate constant is consistent with the measured etching rate behavior. A reactor system in which there is minimum etching of the fused silica chamber by ClF 3 gas can be achieved using an IR lamp heating unit and a chamber cooling unit to maintain a sufficiently low temperature of the chamber wall.

High-Temperature Reactor Cleaning Using Chlorine Trifluoride Gas for Silicon Carbide Chemical Vapor Deposition

“…The chlorine trifluoride gas etches the quartz at the rate near that of semiconductor silicon carbide at high temperatures. 13 Thus, the quartz thickness should be designed accounting for the loss by the etching. For the quartz parts maintained and used for long time at room temperature, the yttrium oxide is found to be the suitable coating film, as reported in our previous study.…”

Lowest Concentration of Chlorine Trifluoride Gas for Cleaning Silicon Carbide Chemical Vapor Deposition Reactor

“…While the quartz tube surface is etched off at high temperatures, the etching rate is significantly reduced in proportion to the chlorine trifluoride gas concentration. 4,22 Such corrosion can be further avoided by using a yttrium oxide coating film. 23 The rubber gasket made of a fluorocarbon, such as Viton ® , is safely used for the 1% chlorine trifluoride gas, in addition to the highly anticorrosive rubber gasket, such as Kalrez ® , which is necessary for the 100% condition.…”

Etching of Silicon Carbide Using Chlorine Trifluoride Gas

“…The etching rate of single-crystalline 4H-silicon carbide is numerically calculated [29]. The geometry of horizontal cold-wall reactor, shown in the previous section (Figure 1), is taken into account for a series of calculations.…”

“…In Section 2, details of polycrystalline 3C-silicon carbide etching using chlorine trifluoride gas [23,24] are reviewed, particularly focusing on the etching rate, gaseous products, surface chemical bonds and the surface morphology of the silicon carbide. In Section 3, the dry etching of single-crystalline 4H-silicon carbide using chlorine trifluoride gas [25][26][27][28][29] over the wide temperature range of 570-1570 K is reviewed, particularly about the etching rate, surface chemical reaction rate constant, surface morphology and etch pits.…”