Study of Silicon Nitride Inner Spacer Formation in Process of Gate-all-around Nano-Transistors.

Stacked SiGe/Si structures are widely used as the units for gate-all-around nanowire transistors (GAA NWTs) which are a promising candidate beyond fin field effective transistors (FinFETs) technologies in near future. These structures deal with a several challenges brought by the shrinking of device dimensions. The preparation of inner spacers is one of the most critical processes for GAA nano-scale transistors. This study focuses on two key processes: inner spacer film conformal deposition and accurate etching. The results show that low pressure chemical vapor deposition (LPCVD) silicon nitride has a good film filling effect; a precise and controllable silicon nitride inner spacer structure is prepared by using an inductively coupled plasma (ICP) tool and a new gas mixtures of CH2F2/CH4/O2/Ar. Silicon nitride inner spacer etch has a high etch selectivity ratio, exceeding 100:1 to Si and more than 30:1 to SiO2. High anisotropy with an excellent vertical/lateral etch ratio exceeding 80:1 is successfully demonstrated. It also provides a solution to the key process challenges of nano-transistors beyond 5 nm node.

A Novel Dry Selective Isotropic Atomic Layer Etching of SiGe for Manufacturing Vertical Nanowire Array with Diameter Less than 20 nm.

Semiconductor nanowires have great application prospects in field effect transistors and sensors. In this study, the process and challenges of manufacturing vertical SiGe/Si nanowire array by using the conventional lithography and novel dry atomic layer etching technology. The final results demonstrate that vertical nanowires with a diameter less than 20 nm can be obtained. The diameter of nanowires is adjustable with an accuracy error less than 0.3 nm. This technology provides a new way for advanced 3D transistors and sensors.

Melanoma-derived exosomes induce reprogramming fibroblasts into cancer-associated fibroblasts via Gm26809 delivery.

Cancer-associated fibroblasts (CAFs) are activated fibroblasts and can interact with cancer cells to promote tumor progression. The process of how tumor cells reprogram normal fibroblasts (NFs) to tumor-promoting CAFs regulated by long non-coding RNA (lncRNA) remains incompletely understood. The tumor cells-released exosomes can induce reprogramming of NFs into CAFs. This study aimed to explore the role of melanoma-derived exosomes in regulating NF-CAF transition and to clarify whether lncRNA Gm26809 was involved in this process. The results showed that the exosomes secreted by melanoma cell B16F0 induced reprogramming of fibroblast NIH/3T3 cells into CAFs, as evidenced by increased expression of CAFs markers (α-SMA and FAP) and facilitated cell migration. Mechanistically, B16F0-secreted exosome delivered Gm26809 into NIH/3T3 cells where Gm26809 mediated reprogramming of fibroblast NIH/3T3 cells into CAFs. Furthermore, the conditioned medium from the co-culture of NIH/3T3 cells and B16F0-exosomes facilitated cell proliferation and migration in a melanoma cell line (Cloundman S91), and the effect was abrogated by Gm26809 knockdown in B16F0 cells. In summary, melanoma-derived exosomes facilitate melanoma cell proliferation and migration through reprogramming fibroblasts into tumor-promoting CAFs via transferring Gm26809.