Plasma manufacturers introduce the potential application of germanium in integrated circuits and its etching method (II)

• Categories:Technical Support
• Author:plasma cleaning machine-surface treatment equipment-CRF plasma machine-Sing Fung Intelligent Manufacturing
• Origin:
• Time of issue:2021-04-01
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(Summary description)From the point of view of the author, the use of highly active etching gas seems to be more critical, both the increase of chlorine gas and the use of CHF3 will accelerate the etching of metal components. However, the impact of bombardment bias is not the key, except for the difference of key size, the difference of morphology under high and low bias pressure is not obvious. It can be seen that the further increase of chlorine gas flow will accelerate the formation of the bottom adducted morphology of the germanium alloy side etching, which also indicates that the highly active chemical etching gas is more effective for germanium etching without losing too much photoresists, so as to ensure the effect of side wall profile curve. The other is mainly fluorinated gas etching, the main etching agent is CF4, the product is more volatile GEF4. We can get very smooth shapes. Adding oxygen can adjust the selection ratio of germanium to its alloy, and the ratio is up to 434. This is important because the multilayer structure of germanium is generally epitaxial, and the induced layer and interlayer structure are generally germanium alloy materials. The selection of high ratio process can better control the etching of such multilayer structure. We know that CF4 is also a highly reactive chemical etching gas. From the effect, adding oxygen to CF4 has a higher etching selection ratio, because oxygen is more likely to react with the underlying material (SN) to form a protective surface film, preventing further etching and improving the selection ratio. It seems that the morphology of the CF4 etching is also better, but the advantage of chlorine etching is low damage, and it is good for the interface layer and channel layer. Both chlorine-based and fluorine-based germanium etching are common processes at present, which have achieved good results and have been applied in device manufacturing respectively. Another less common class of germanium is etched using XEF2 gas.