Advanced Materials - Epitaxial Growth of Large-Scale 2D CrTe2 Films on Amorphous Silicon Wafers With Low Thermal Budget

2D van der Waals (vdW) magnets open landmark horizons in the development of innovative spintronic device architectures. However, their fabrication with large scale poses challenges due to high synthesis temperatures (>500 °C) and difficulties in integrating them with standard complementary metal-oxide semiconductor (CMOS) technology on amorphous substrates such as silicon oxide (SiO2) and silicon nitride (SiNx). Here, a seeded growth technique for crystallizing CrTe2 films on amorphous SiNx/Si and SiO2/Si substrates with a low thermal budget is presented. This fabrication process optimizes large-scale, granular atomic layers on amorphous substrates, yielding a substantial coercivity of 11.5 kilo-oersted, attributed to weak intergranular exchange coupling. Field-driven Néel-type stripe domain dynamics explain the amplified coercivity. Moreover, the granular CrTe2 devices on Si wafers display significantly enhanced magnetoresistance, more than doubling that of single-crystalline counterparts. Current-assisted magnetization switching, enabled by a substantial spin–orbit torque with a large spin Hall angle (85) and spin Hall conductivity (1.02 ×  107 ℏ/2e  Ω⁻¹  m⁻¹), is also demonstrated. These observations underscore the proficiency in manipulating crystallinity within integrated 2D magnetic films on Si wafers, paving the way for large-scale batch manufacturing of practical magnetoelectronic and spintronic devices, heralding a new era of technological innovation.

二维范德华（van der Waals, vdW）磁体为创新型自旋电子器件架构的发展开辟了里程碑式的新前景。然而，由于合成温度高昂（＞500℃），且难以将其与氧化硅（SiO₂）、氮化硅（SiNₓ）等非晶衬底上的标准互补金属氧化物半导体（CMOS）工艺集成，其大规模制备仍面临诸多挑战。本文报道了一种籽晶生长技术，可在低热预算条件下于非晶SiNₓ/Si及SiO₂/Si衬底上制备碲化铬（CrTe₂）薄膜。该制备工艺可优化非晶衬底上的大规模颗粒状原子层结构，获得高达11.5千奥斯特的显著矫顽力，这一性能归因于弱晶间交换耦合作用。场驱动奈尔型条畴动力学机制可解释该矫顽力的增强效应。此外，硅晶圆上的颗粒状CrTe₂器件展现出显著提升的磁阻性能，其数值较单晶样品翻倍以上。借助自旋霍尔角为85、自旋霍尔电导率达1.02×10⁷ ℏ/2e Ω⁻¹·m⁻¹的强自旋轨道转矩，本文还实现了电流辅助磁化翻转。上述研究结果证明了在硅晶圆集成的二维磁性薄膜中精准调控结晶度的可行性，为实用型磁电子与自旋电子器件的大规模批量制造铺平了道路，开启了科技创新的崭新时代。