Dear editor,rnThree-dimensional monolithic integration(3D-MI)has recently emerged for both“more Moore”and“more than Moore”applications,because of its high integration density,high bandwidth and multi-functions[1].With 3D-MI,different types of devices can be stacked on the same platform and in a single process flow.A critical issue for 3D-MI is the formation of high-quality channels for the devices on the upper level under the constraints of low thermal budget and low cost.Several ef-forts have been reported to realize poly-Si thin film channels on SiO2 at low temperature,for example,laser annealing(LA)[2],solid phase crystallization(SPC)[3],and metal-induced lateral crystalliza-tion(MILC)[4].LA can obtain a single-crystal-like thin film,but needs extraordinary atomic-level chemical-mechanical polishing(CMP)to reduce surface roughness,which results in high process variation and cost.SPC is a common and simple technique,but its crystallization rate is too slow to efficiently form the active layer,and the random self-nucleation mechanism can lead to large fluctu-ations in grain size.MILC is another cost-effective method that can improve the crystallization rate,but suffers from serious metal contamination and a large number of dislocation defects in silicon grains because of metal-silicon inter-diffusion.