Dry etching of silicon carbide in ICP with high anisotropy and etching rate

Abstract

A detailed study of the influence of technological parameters of the plasma chemical etching process in inductively coupled plasma on the etching rate of single-crystal silicon carbide is presented. The physicochemical substantiation of experimentally revealed patterns is given. The optimal gas mixture was determined in terms of the etching rate of SiC. It was experimentally established that the dependence of the etching rate of silicon carbide on the percentage of oxygen in the total gas mixture is non-linear. Thus, with an increase in the percentage of O2 up to 23%, the etching rate of SiC gradually increases to 560 nm/min, a further increase in the percentage of O2 leads to a sharp decrease in the etching rate of SiC up to 160 nm/min at an oxygen content of 31%. The effect of the distance between the sample and the plasma generation zone on the etching rate of SiC was studied. It was shown that the greatest increase in speed is caused by an increase in the bias voltage, so at Ubias = - 50 V the etching rate is 300 nm/min, and at Ubias = - 150 V the value of the etching rate is 840 nm/min. The optimal parameters of the plasma-chemical etching process were selected for high-speed directional etching of single-crystal silicon carbide substrates.

A Review: Inductively Coupled Plasma Reactive Ion Etching of Silicon Carbide

“…It was experimentally established that the dependance of the etching rate of silicon carbide on the percentage of oxygen in the total gas mixture is non-linear [ 47 ]. It was observed that the addition of 20–25% oxygen for SiC etching in SF 6 + O 2 plasma is optimal for the highest etching rates [ 23 , 42 , 47 ].…”

“…It was experimentally established that the dependance of the etching rate of silicon carbide on the percentage of oxygen in the total gas mixture is non-linear [ 47 ]. It was observed that the addition of 20–25% oxygen for SiC etching in SF 6 + O 2 plasma is optimal for the highest etching rates [ 23 , 42 , 47 ]. In the process of chemical interaction of reactive fluorine ions with silicon, volatile SiF x (1 < x < 4) compounds are formed, and an addition of the oxygen to plasma increases the etching rate of the carbon-rich SiC surface layer as a result of the formation of volatile compounds in the form of CO, CO 2 [ 42 ] and COF 2 [ 39 ].…”

Creation and Optimisation of Plasma Etch Processes for the Manufacture of Silicon Microstructures

“…Plasma etch technology would be compatible with other materials for the creation of MN, given the right process flow. Although significantly more expensive, Silicon Carbide (SiC) [194,195] is one such material of interest due to its compatibility with dry etch processing [196][197][198] and the mechanical advantages it holds over silicon [195].…”