Excimer laser dopant activation for monolithic 3-dimensional structure

Abstract

In the semiconductor industry, device miniaturization has attracted attention because it can simultaneously improve device performance and increase profits. However, as the size of transistors becomes too small, the miniaturization of semiconductors has reached a limit due to the complexity of nanoscale processes, resistive capacitance delays, and increased energy consumption from complex metal lines. In order to overcome these limitations, a monolithic three-dimensional structure in which the degree of transistor integration is increased with a stacked structure and electrical efficiency is improved through short metal wires has been proposed. Most of the CMOS process can be used during lower layer device formation. However, a dopant activation process using a high-temperature (1000°C) RTA cannot be used for upper layer device formation, due to low thermal durability of the metal wiring and underlying devices. In this study, excimer laser annealing enabled dopant activation in a monolithic 3D structure, finally realizing a monolithic 3D semiconductor structure