Reactive ion etching of SiC using C2F6/O2 inductively coupled plasma

Abstract

The inductively coupled plasma-reactive ion etching (ICP-RIE) of SiC single crystals using the C 2 F 6 /O 2 gas mixture was investigated. It was observed that the etch rate increased as the ICP power and bias power increased. With increasing sample-coil distance, O 2 concentration, and chamber pressure, the etch rate initially increased, reached a maximum, and then decreased. Mesas with smooth surfaces (roughness Յ 1 nm) and vertical sidewalls (ϳ85°) were obtained at low bias conditions with a reasonable etch rate of about 100 nm/min. A maximum etch rate of 300 nm/min could be obtained by etching at high bias conditions (Ն300 V), in which case rough surfaces and the trenched sidewall base were observed. The trenching effect could be suppressed by etching the samples on anodized Al plates, although mesas with sloped (60-70°) sidewalls were obtained. Results of various surface characterization indicated little contamination and damage on the etched SiC surfaces. 210Kong, Choi, Lee, Han, and Lee Fig. 1. Etch characteristics of 6H-SiC and 4H-SiC as a function of (a) ICP source power, (b) bias power, (c) pressure, (d) O 2 percentage in C 2 F 6 /O 2 , and (e) the distance between the substrate holder and the source coil.

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

“…Similar trends in the dependence of the SiC etching rate on the applied power have been reported in literature, e.g., for SF 6 + O 2 , C 2 F 6 + O 2 or SF 6 + He gas mixtures [7,22,30,41,42,44,52]. It should be noticed that in case of relationship between the SiC etching rate and ICP power, in literature have been reported results for lower ICP power range, i.e., below 1000 W [22,30,44,52]. Our investigations presented in this paper extend this ICP power range considerably up to 2500 W.…”

“…Figures 12 and 15 show that the SiC etching rate in the SF 6 plasma can be improved by increasing the applied RIE power or ICP power, and it increases with them. Similar trends in the dependence of the SiC etching rate on the applied power have been reported in literature, e.g., for SF 6 + O 2 , C 2 F 6 + O 2 or SF 6 + He gas mixtures [7,22,30,41,42,44,52]. It should be noticed that in case of relationship between the SiC etching rate and ICP power, in literature have been reported results for lower ICP power range, i.e., below 1000 W [22,30,44,52].…”

“…This SiC etching rate value is very closed to the SiC etching rate of ~500 nm/min reported by Jiang et al [44] for etching in SF 6 /O 2 /Ar gas mixture with ~30% Ar as optimal concentration. It is also worth mentioning that when etching of SiC in a different plasma-C 2 F 6 + O 2 -it was shown that the etching rate increases with the addition of more O 2 , reaches its maximum at around 60% of O 2 , and then decreases [52]. On the other hand, only a slight and monotonical increase in SiC etching rate was observed at 40% of O 2 content by Sugiura et al [41] for SiC etching in the CF 4 + O 2 mixture.…”

Characteristics of Silicon Carbide Etching Using Magnetized Inductively Coupled Plasma

“…[3][4][5][6] To etch SiC at high rates, high density plasma sources, such as the electron cyclotron resonance (ECR) plasma, helicon plasma and inductively coupled plasma (ICP), have been investigated. [7][8][9] Among these different plasma sources, inductively coupled plasma sources are widely used, because of the high rate of etching that can be achieved for various materials including SiC, due to their simple source structure and physical properties, as well as their scalability to large area substrates. 3) As far as the process gas is concerned, for the high rate etching of SiC, fluorine-based gases are generally used, however, due to the low etch selectivity of SiC to photoresist, other mask materials having higher etch resistance to fluorine based gases, such as Al, indium tin oxide (ITO) and Ni, have also been used, in order to increase the etch selectivity and to obtain a smoother and more anisotropic etch profile.…”

Use of a neural network to model SiC etching in a NF3inductively coupled plasma

“…Silicon carbide (SiC) is an important electronic material in manufacturing high power devices. Plasma etching is a key means to achieve desired SiC patterns [1][2][3][4][5][6][7][8][9][10][11][12][13][14]. The SiC films have been etched in fluorine-based SF 6 , NF 3 or C 2 F 6 chemistries.…”