Low temperature and ion-cut based monolithic 3D process integration platform incorporated with CMOS, RRAM and photo-sensor circuits

Abstract

We demonstrated low temperature (< 500 °C) and hydrogen ion-cut based monolithic 3D (M3D) process integration platform with CMOS circuits, memory devices and photo-sensitive sensors. Top Si layer was transferred on the 8-inch bottom Si substrate having standard CMOS circuits using hydrogen ion implantation, bonding and cleavage under low thermal annealing. Ta2O5-RRAM and a-IGZO photo detector devices on the upper transferred Si layer were vertically stacked with CMOS circuits. Bonding and top Si layer transfer are considerably affected by ion implantation process, ILD, surface treatment, oxide CMP and annealing. Different light intensity to photodetector at the upper layer modulates the frequency of current sensor with 21 stage ring- oscillator at the lower layer and current level in RRAM at the upper layer is also modulated by input frequency from CMOS devices. The functionalities of ion-cut based M3D integration platform are confirmed by higher frequency and current level with respect to light intensity.