Two-dimensional semiconductor materials, represented by transition metal dichalcogenides (TMDCs), have the characteristics of extreme thickness, high mobility, and back-end heterogeneous integration. They are expected to continue Moore's law and realize integrated circuits with three-dimensional architecture. and industry attention. After nearly a decade of development, two-dimensional electronics has made great progress, but there are still challenges in the preparation of large-area single crystals, key device processes, and compatibility with mainstream semiconductor technologies.
Forskergruppen af prof. Xinran Wang fra School of Electronic Science and Engineering ved Nanjing University fokuserede på ovenstående problemer og forskede i gennembrud inden for nøgleteknologierne inden for to-dimensionel halvleder-enkeltkrystalfabrikation og hetero- integration, som gav nye ideer til udvikling af integrerede kredsløb i Moore-æraen efter-. Relevante forskningsresultater er blevet offentliggjort i Nature Nanotechnology for nylig.
Building "atomic terraces" down-to-earth, breaking through two-dimensional semiconductor single crystal epitaxy
Halvleder-enkrystalmaterialer er hjørnestenen i mikroelektronikindustrien. Sammenlignet med de almindelige 12-tommer monokrystallinske siliciumwafere er fremstillingen af to-dimensionelle halvledere stadig i den lille-skala og polykrystallinske fase. Udviklingen af monokrystallinske tynde film med store-arealer af-kvalitet er det første skridt mod to-integrerede kredsløb. . Men under væksten af to-dimensionelle materialer genereres millioner af mikroskopiske chips tilfældigt, og det er kun muligt at opnå et monolitisk enkeltkrystalmateriale ved at kontrollere alle chips for at opretholde en strengt konsistent arrangementsretning.
Sapphire is a widely used substrate in the semiconductor industry and has outstanding advantages in mass production, low cost and process compatibility. The collaborating team proposed a scheme to artificially construct atomic-scale "terraces" by changing the direction of the atomic steps on the sapphire surface. The directional growth of TMDCs was achieved by the directional induced nucleation mechanism of "atomic terraces".
Based on this principle, the team achieved the epitaxial growth of a 2-inch MoS2 single crystal film for the first time in the world. Thanks to the improvement of material quality, the mobility of field effect transistors based on MoS2 single crystal is as high as 102.6 cm2/Vs, and the current density reaches 450 μA/μm, which is one of the highest comprehensive performances reported internationally. At the same time, the technology has good universality and is suitable for the preparation of single crystals of other materials such as MoSe2. This work has laid a material foundation for the application of TMDC in the field of integrated circuits.
Når du ser op på stjernerne, bringer to-halvledere lys til fremtidens skærmteknologi
Gennembruddet af enkeltkrystalmaterialer med store-arealer gør det muligt for to-dimensionelle halvledere at blive anvendt. I det andet arbejde, baseret på års akkumulering af tredje-generations halvlederforskning, kombineret med den seneste to-dimensionelle halvleder-enkrystalløsning, foreslog det samarbejdsvillige team fra School of Electronics en monolitisk integreret ultra -høj- Micro LED-skærm baseret på MoS2 tyndfilm transistor-driverkredsløb. Tekniske løsninger.
Micro LED refererer til en teknologi, der bruger mikron-skala-LED'er som lysemitterende pixelenheder og samler dem med drivmoduler for at danne en visningsarray med høj-densitet. Sammenlignet med de nuværende almindelige skærmteknologier såsom LCD og OLED, har Micro LED tværgenerationsfordele i form af lysstyrke, opløsning, energiforbrug, levetid, responshastighed og termisk stabilitet og er en internationalt anerkendt næste-. {4}}generations displayteknologi.
Industrialiseringen af Micro LED står dog stadig over for mange udfordringer. For det første er det svært at matche kørselskravene til skærmenheder med høj-densitet i små størrelser. For det andet er masseoverførselsteknologien, der er populær i branchen, vanskelig at opfylde udviklingsbehovene for skærme med høj-opløsning med hensyn til omkostninger og udbytte. Især for applikationer med ultra-høj-opløsning, såsom AR/VR, skal opløsningen ikke kun overstige 3000PPI, men også skærmpixelerne skal have en hurtigere responsfrekvens.
The cooperative team aimed at the field of high-resolution micro-display, and proposed a technical solution for the 3D monolithic integration of MoS2 thin-film transistor driver circuit and GaN-based Micro LED display chip. The team developed a non-"massive transfer" low-temperature monolithic heterogeneous integration technology, using a nearly non-destructive large-size two-dimensional semiconductor TFT manufacturing process, to achieve a high-brightness, high-resolution microdisplay of 1270 PPI, which can meet the needs of future microdisplays. Display, vehicle display, visible light communication and other cross-field applications.
Among them, compared with the traditional two-dimensional semiconductor device process, the new process developed by the team improves the performance of thin film transistors by more than 200 percent , reduces the difference by 67 percent , and the maximum driving current exceeds 200 μA/μm, which is better than IGZO, LTPS and other commercial materials. It shows the huge application potential of two-dimensional semiconductor materials in the display driving industry. This work is the first in the world to integrate two emerging technologies of high-performance two-dimensional semiconductor TFT and Micro LED, which provides a new technical route for the future development of Micro LED display technology.
The above works are respectively named "Epitaxial growth of wafer-scale molybdenum disulfide semiconductor single crystals on sapphire" (corresponding authors are Prof. Wang Xinran and Prof. Wang Jinlan of Southeast University) and "Three dimensional monolithic Micro LED display driven by atomically-thin transistor matrix" (corresponding authors). It was published online in Nature Nanotechnology recently.
This series of work has been supported by projects such as Jiangsu Province's Frontier Leading Technology Basic Research Project, the National Natural Science Foundation of China, and the National Key RD Program. Changchun Institute of Optics and Mechanics, Chinese Academy of Sciences, Tianma Microelectronics Co., Ltd., Nanjing Huanxuan Semiconductor Co., Ltd., etc.
