Effects of Stacked Al2O3 / HFO2 Films Deposited in Deep Trench Isolation on White Pixels Noise

In the stacked-BSI CMOS image sensor process, deposition of high-k thin films in deep trench isolation (DTI) to further reduce white pixels noise has attracted lots of attention. In this paper, we explore the influence of stacked two films of Al
2
O
3
/HfO
2
on the white pixel properties of the CMOS image sensor. Here, the two oxide layers are deposited using PEALD. We found that the as-deposited Al
2
O
3
/ HfO
2
(TH1/TH1) films show a suppression of the white pixels up to 175 PPM(P95). This achievement could open a possible way to remarkably further reduce the white pixels noise.