First Demonstration of Heterogeneous IGZO/Si CFET Monolithic 3D Integration with Dual Workfunction Gate for Ultra Low-power SRAM and RF Applications
Journal
Technical Digest - International Electron Devices Meeting, IEDM
Journal Volume
2021-December
Pages
34.4.1-34.4.4
Date Issued
2021
Author(s)
Chang S.-W
Lu T.-H
Yang C.-Y
Yeh C.-J
Huang M.-K
Meng C.-F
Chen P.-J
Chang T.-H
Chang Y.-S
Jhu J.-W
Hong T.-Z
Ke C.-C
Yu X.-R
Lu W.-H
Baig M.A
Cho T.-C
Sung P.-J
Su C.-J
Hsueh F.-K
Chen B.-Y
Hu H.-H
Wu C.-T
Lin K.-L
Ma W.C.-Y
Lu D.-D
Kao K.-H
Lee Y.-J
Lin C.-L
Huang K.-P
Chen K.-M
Li Y
Samukawa S
Chao T.-S
Huang G.-W
Wu W.-F
Lee W.-H
Shieh J.-M
Tarng J.-H
Wang Y.-H
Yeh W.-K.
Abstract
In this work, we demonstrate vertically stacked heterogeneous dual-workfunction gate complementary FET (CFET) inverters and 6T-SRAM with n-Type IGZO and p-Type polysilicon channels for the first time. The dual-workfunction gate structure with adjusted gate biasing allows the adjustment of channel potential to match the threshold voltage of transistors for CMOS and SRAM operation. High-frequency IGZO RF devices with p-Type silicon isolation are fabricated simultaneously with the same process. Novel etching process based on fluorine-based gas with an extremely high-etching selectivity between the source/drain metal and the IGZO facilitates the definition of the source/drain region. IGZO surface treated with fluorine-based gas during over-etching step allows a low leakage current shallow passivation layer to optimize direct current characteristics. © 2021 IEEE.
Other Subjects
Etching; Fluorine; Leakage currents; Passivation; Semiconducting indium compounds; Thin film transistors; Three dimensional integrated circuits; 3-D integration; 6T-SRAM; 6T-SRAMs; Fluorine-based gas; Low power RF; Low-power SRAM; Monolithics; RF applications; SRAM applications; Ultra-low power; Threshold voltage
Type
conference paper