In semiconductor technology, integrated circuits are formed on a substrate using various technologies including photolithography process, etching and deposition. Compared with the half-century development of Si and compound semiconductors, the study of two-dimensional crystal graphene with its first discovery at 2004 is still at a very early stage. Nevertheless, the theoretically predicted high mobility of graphene has already emerged its possible application in high-speed electronics. Owing to its wide absorption wavelengths and short carrier lifetime, graphene also has strong potential for optical devices.
However, both the device structure and corresponding method making the same are still long way to go. There are various issues to be solved and challenges to overcome. Chemical vapor deposition (CVD) is now a promising method for large-area and uniform 2-D crystal growth. Graphene and transition metal dichalcogenides (TMDs) have been demonstrated by using CVD. However, for different 2-D crystals, different precursors have to be chosen located and adopted for growth. For example, CH4 is used as precursor for graphene growth. In this case, if 2-D crystal hetero-structures are to be prepared for practical applications, suitable precursors have to be located for different 2-D crystals, which will be an issue in the advanced researches for unknown materials. On the other hand, CVD technique is advantageous for large-area film growth. However, it is difficult to achieve selective growth by using this method. The possible high dependence of 2-D crystal growth on certain substrates such as sapphire has also limited the applications of these materials. Film transferring procedures have to be conducted to transfer the 2-D crystals from sapphire to desired substrates. Furthermore, the device structure made from 2-D crystals is not mature and need to be adjusted and tuned to overcome the issues associated with the 2-D crystals and maximize the use of the 2-D crystals. Therefore, the present disclosure provides a semiconductor structure and a method making the same to address the above issues.
USPTO Backgrounds
USPTO Backgrounds