Monolithic 3D-ICs with single grain Si thin film transistors

Abstract

We propose monolithic 3D-ICs based on single grain Si TFTs where transistors are fabricated inside a silicon grain. Location of the grain was controlled by the µ-Czochralski process which is based on pulsed-laser crystallization of a-Si. Two single-grain TFTs layers were monolithically stacked with electron and hole mobilities of 600 cm2/Vs and 200 cm2/Vs, respectively. Electrical properties are presented of fabricated 6T-SRAM and lateral photodiodes with in-pixel amplifier. Photodiode pixels have a light sensitivity of 100 while SRAM cells fabricated in 128F2 area shows a static noise margin of 0.75V with a supply voltage of 5V.