Demonstration of TFTs 3D Monolithically Integrated on GaN HEMTs using Cascode Configuration with High Breakdown Voltage (>1900V)

TL;DR

This paper demonstrates the successful 3D monolithic integration of a-IGZO TFTs on GaN HEMTs in a cascode configuration, achieving high breakdown voltages over 1900 V and promising high-voltage application potential.

Contribution

It introduces a novel 3D monolithic integration method of TFTs on GaN HEMTs with high voltage performance, which was not previously demonstrated.

Findings

Achieved breakdown voltage >1900 V in integrated devices

Sample with 10 nm a-IGZO channel shows high ON/OFF ratio (~10^7)

Demonstrated comparable performance to standalone GaN HEMTs

Abstract

This study demonstrates 3D monolithic integration of amorphous indium-gallium-zinc oxide (a-IGZO) thin-film transistors (TFTs) on Gallium Nitride (GaN) high electron mobility transistors (HEMTs) in a cascode configuration, achieving high breakdown voltage capabilities exceeding 1900 V. Two device configurations, differing in a-IGZO channel thickness (30 nm / 10 nm), are fabricated and evaluated. Sample B, with a 10 nm a-IGZO channel, demonstrates superior electrical performance, including a high ON/OFF current ratio (~10^7), low subthreshold swing (SS), and a high breakdown voltage exceeding 1900 V comparable to standalone GaN power HEMTs. The results highlight the feasibility and potential of 3D integrated TFT on GaN power HEMTs, paving the way for new opportunities for the TFTs for high voltage applications.