Gated Hall and field-effect transport characterization of e-mode ZnO TFTs

Gated Hall and field-effect transport characterization of e-mode ZnO TFTs

Bibliographic Details
Main Author: Anders, Jason C.
Language:English
Published: Wright State University / OhioLINK 2021
Subjects:
Electrical Engineering
gated Hall
electronic transport
mobility
Online Access:http://rave.ohiolink.edu/etdc/view?acc_num=wright1628759244201245
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spelling ndltd-OhioLink-oai-etd.ohiolink.edu-wright16287592442012452021-08-21T05:13:27Z Gated Hall and field-effect transport characterization of e-mode ZnO TFTs Anders, Jason C. Electrical Engineering gated Hall electronic transport mobility Amorphous and nano-crystalline metal oxide semiconductors are an important class of materials under continuing investigation for emerging technologies. Accurate measurements of electron mobility in these materials is critical for furthering overall device development. This is complicated due to the fact that device measurements such as current response, transistor input and output characteristics, as well as mobility are affected by transport-limiting factors, such as charge trapping effects at the dielectric / active layer interface, and restriction of electronic transport across grain boundaries. In this work, we focus on the binary metal oxide thin film transistor (ZnO TFT), a normally-off (e-mode) transistor with a positive threshold voltage (Vth) and a large ( > 10 MΩ)) sheet resistance at gate voltage below threshold (VG < Vth), Field-effect and Hall (extrinsic and intrinsic mobilities) were measured on the same device at the same time (concurrent mobility measurements of our gated Hall system) at device relevant dimensions (25 nm Al2O3, gate dielectric, 50 nm ZnO active layer), at typical transistor gate and drain bias device operating conditions (VG < 10 V and VD biased in the linear region), on the same device (100 × 100 µm Van der Pauw). The large sheet resistance (RS) of the material requires electrostatic doping (by gate bias) in order to modulate resistance and increase Hall test current. However, as VG interacts with VD and VS, resulting vertical electric fields EGS and EGD must remain below dielectric breakdown (EBD). The result of meeting these test requirements led to a fully automated gated Hall test system capable of making measurements and comparisons of mobility across the allowable test bias spectrum (VG and VD). A design of experiment in which test wafers were compared between in situ deposition and exposure to clean room ambient air between the dielectric and active layer depositions (by atomic layer deposition) was used to examine interface effects. Post temperature oven annealing was used to compare differences in grain boundary effects by increasing grain size. A simple model of two transport regimes was developed (localized and non-localized transport) to fit several contradictory trends observed in the measured data sets. 2021-08-20 English text Wright State University / OhioLINK http://rave.ohiolink.edu/etdc/view?acc_num=wright1628759244201245 http://rave.ohiolink.edu/etdc/view?acc_num=wright1628759244201245 restricted--full text unavailable until 2022-08-20 This thesis or dissertation is protected by copyright: all rights reserved. It may not be copied or redistributed beyond the terms of applicable copyright laws.
collection NDLTD
language English
sources NDLTD
topic Electrical Engineering
gated Hall
electronic transport
mobility
spellingShingle Electrical Engineering
gated Hall
electronic transport
mobility
Anders, Jason C.
Gated Hall and field-effect transport characterization of e-mode ZnO TFTs
author Anders, Jason C.
author_facet Anders, Jason C.
author_sort Anders, Jason C.
title Gated Hall and field-effect transport characterization of e-mode ZnO TFTs
title_short Gated Hall and field-effect transport characterization of e-mode ZnO TFTs
title_full Gated Hall and field-effect transport characterization of e-mode ZnO TFTs
title_fullStr Gated Hall and field-effect transport characterization of e-mode ZnO TFTs
title_full_unstemmed Gated Hall and field-effect transport characterization of e-mode ZnO TFTs
title_sort gated hall and field-effect transport characterization of e-mode zno tfts
publisher Wright State University / OhioLINK
publishDate 2021
url http://rave.ohiolink.edu/etdc/view?acc_num=wright1628759244201245
work_keys_str_mv AT andersjasonc gatedhallandfieldeffecttransportcharacterizationofemodeznotfts
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