Nanoscale Film Thickness Gradients Printed in Open Air by Spatially Varying Chemical Vapor Deposition

Abstract

Nanoscale films are integral to all modern electronics. To optimize device performance, researchers vary the film thickness by making batches of devices, which is time-consuming and produces experimental artifacts. Thin films with nanoscale thickness gradients that are rapidly deposited in open air for combinatorial and high-throughput (CHT) studies are presented. Atmospheric pressure spatial atomic layer deposition reactor heads are used to produce spatially varying chemical vapor deposition rates on the order of angstroms per second. ZnO and Al 2 O 3 films are printed with nm-scale thickness gradients in as little as 45 s and CHT analysis of a metal-insulator-metal diode and perovskite solar cell is performed. By testing 360 Pt/Al 2 O 3 /Al diodes with 18 different Al 2 O 3 thicknesses on one wafer, a thicker insulator layer (≈7.0 nm) is identified for optimal diode performance than reported previously. Al 2 O 3 thin film encapsulation is deposited by atmospheric pressure chemical vapor deposition (AP-CVD) on a perovskite solar cell stack for the first time and a convolutional neural network is developed to analyze the perovskite stability. The rapid nature of AP-CVD enables thicker films to be deposited at a higher temperature than is practical with conventional methods. The CHT analysis shows enhanced stability for 70 nm encapsulation films.

Nanometric 3D Printing of Functional Materials by Atomic Layer Deposition

“…To overcome this limitation, D. Muñoz-Rojas' group at the Laboratoire des Matériaux et du Génie Physique (LMGP, Grenoble, France) has introduced the utilization of 3D printing for the fabrication of customized SALD injection heads [41]. This allows having more freedom to design the head and, for example, the gas distribution can be incorporated in the body of the head (Figure 4b and c) [41][42][43]. Plastic heads can be printed for depositions taking place at low temperatures while metal 3D printing is also possible for higher temperatures [44].…”