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.
Kelompok penelitian Prof. Xinran Wang dari Sekolah Ilmu dan Teknik Elektronik Universitas Nanjing berfokus pada masalah di atas dan meneliti terobosan dalam teknologi kunci dari dua-semikonduktor dimensi fabrikasi kristal tunggal dan hetero- integrasi, yang memberikan ide-ide baru untuk pengembangan sirkuit terpadu di era pasca-Moore. Hasil penelitian yang relevan telah dipublikasikan di Nature Nanotechnology baru-baru ini.
Building "atomic terraces" down-to-earth, breaking through two-dimensional semiconductor single crystal epitaxy
Bahan kristal tunggal semikonduktor adalah landasan industri mikroelektronika. Dibandingkan dengan wafer silikon monokristalin 12-inci arus utama, persiapan dua-semikonduktor dimensi masih dalam tahap-kecil dan polikristalin. Pengembangan film tipis monokristalin-area yang luas-berkualitas tinggi adalah langkah pertama menuju sirkuit terpadu dua-dimensi. . Namun, selama pertumbuhan material dua-dimensi, jutaan chip mikroskopis dihasilkan secara acak, dan hanya mungkin untuk mendapatkan material kristal tunggal monolitik dengan mengontrol semua chip untuk mempertahankan arah pengaturan yang sangat konsisten.
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.
Menatap bintang-bintang, semikonduktor dua-dimensi membawa cahaya ke teknologi tampilan masa depan
Terobosan bahan kristal-area tunggal-yang besar memungkinkan semikonduktor dua-dimensi untuk diterapkan. Dalam karya kedua, berdasarkan akumulasi tahun ketiga-penelitian semikonduktor generasi ketiga, dikombinasikan dengan solusi kristal tunggal semikonduktor dua-dimensi terbaru, tim kerja sama School of Electronics mengusulkan ultra Layar LED Mikro beresolusi -tinggi-berdasarkan rangkaian driver transistor film tipis MoS2. Solusi teknis.
Micro LED mengacu pada teknologi yang menggunakan mikron-LED skala sebagai unit piksel yang memancarkan-cahaya dan merakitnya dengan modul penggerak untuk membentuk rangkaian tampilan-densitas tinggi. Dibandingkan dengan teknologi layar utama saat ini seperti LCD dan OLED, Micro LED memiliki keunggulan lintas-generasi dalam hal kecerahan, resolusi, konsumsi energi, masa pakai, kecepatan respons, dan stabilitas termal, dan merupakan produk berikutnya yang diakui secara internasional{ {4}}teknologi tampilan generasi.
Namun, industrialisasi Micro LED masih menghadapi banyak tantangan. Pertama, sulit untuk mencocokkan persyaratan mengemudi unit tampilan-densitas tinggi dalam ukuran kecil. Kedua, teknologi transfer massal yang populer di industri ini sulit untuk memenuhi kebutuhan pengembangan tampilan resolusi tinggi-dalam hal biaya dan hasil. Khusus untuk aplikasi resolusi ultra-tinggi-seperti AR/VR, tidak hanya resolusi yang diperlukan untuk melebihi 3000PPI, tetapi juga piksel tampilan harus memiliki frekuensi respons yang lebih cepat.
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.
