東華大學圖書館 |

語系: 繁體中文

說明(常見問題)

回圖書館首頁

手機版館藏查詢

登入

回首頁

切換: 標籤 | MARC模式 | ISBD

Electron Microscopy Characterization...

Peri, Prudhvi Ram.

FindBook

Google Book

Amazon

博客來

Electron Microscopy Characterization of GaN-on-GaN Vertical Power Devices = = Electron Microscopy Characterization of GaN-on-GaN Vertical Power Devices .

紀錄類型:	書目-電子資源 : Monograph/item
正題名/作者:	Electron Microscopy Characterization of GaN-on-GaN Vertical Power Devices =/
其他題名:	Electron Microscopy Characterization of GaN-on-GaN Vertical Power Devices .
作者:	Peri, Prudhvi Ram.
出版者:	Ann Arbor : ProQuest Dissertations & Theses, : 2021,
面頁冊數:	129 p.
附註:	Source: Dissertations Abstracts International, Volume: 82-11, Section: B.
Contained By:	Dissertations Abstracts International82-11B.
標題:	Electrical engineering. -
電子資源:	https://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=28419227
ISBN:	9798728271307

Electron Microscopy Characterization of GaN-on-GaN Vertical Power Devices = = Electron Microscopy Characterization of GaN-on-GaN Vertical Power Devices .
Peri, Prudhvi Ram.

Electron Microscopy Characterization of GaN-on-GaN Vertical Power Devices =Electron Microscopy Characterization of GaN-on-GaN Vertical Power Devices . - Ann Arbor : ProQuest Dissertations & Theses, 2021 - 129 p.

Source: Dissertations Abstracts International, Volume: 82-11, Section: B.

Thesis (Ph.D.)--Arizona State University, 2021.

This item must not be sold to any third party vendors.

Wide bandgap semiconductors are of much current interest due to their superior electrical properties. This dissertation describes electron microscopy characterization of GaN-on-GaN structures for high-power vertical device applications. Unintentionally-doped (UID) GaN layers grown homoepitaxially via metal-organic chemical vapor deposition on freestanding GaN substrates, were subjected to dry etching, and layers of UID-GaN/p-GaN were over-grown. The as-grown and regrown heterostructures were examined in cross-section using transmission electron microscopy (TEM). Two different etching treatments, fast-etch-only and multiple etches with decreasing power, were employed. The fast-etch-only devices showed GaN-on-GaN interface at etched location, and low device breakdown voltages were measured (~ 45-95V). In comparison, no interfaces were visible after multiple etching steps, and the corresponding breakdown voltages were much higher (~1200-1270V). These results emphasized importance of optimizing surface etching techniques for avoiding degraded device performance. The morphology of GaN-on-GaN devices after reverse-bias electrical stressing to breakdown was investigated. All failed devices had irreversible structural damage, showing large surface craters (~15-35 microns deep) with lengthy surface cracks. Cross-sectional TEM of failed devices showed high densities of threading dislocations (TDs) around the cracks and near crater surfaces. Progressive ion-milling across damaged devices revealed high densities of TDs and the presence of voids beneath cracks: these features were not observed in unstressed devices. The morphology of GaN substrates grown by hydride vapor-phase epitaxy (HVPE) and by ammonothermal methods were correlated with reverse-bias results. HVPE substrates showed arrays of surface features when observed by X-ray topography (XRT). All fabricated devices that overlapped with these features had typical reverse-bias voltages less than 100V at a leakage current limit of 10-6 A. In contrast, devices not overlapping with such features reached voltages greater than 300V. After etching, HVPE substrate surfaces showed defect clusters and macro-pits, whereas XRT images of ammonothermal substrate revealed no visible features. However, some devices fabricated on ammonothermal substrate failed at low voltages. Devices on HVPE and ammonothermal substrates with low breakdown voltages showed crater-like surface damage and revealed TDs (~25µm deep) and voids; such features were not observed in devices reaching higher voltages. These results should assist in developing protocols to fabricate reliable high-voltage devices.

ISBN: 9798728271307Subjects--Topical Terms:

649834
Electrical engineering.
Subjects--Index Terms:

Defects

Electron Microscopy Characterization of GaN-on-GaN Vertical Power Devices = = Electron Microscopy Characterization of GaN-on-GaN Vertical Power Devices .
LDR:04110nmm a2200457 4500 001 2280679
005 20210907071130.5
008 220723s2021 ||||||||||||||||| ||eng d
020 $a 9798728271307
035 $a (MiAaPQ)AAI28419227
035 $a AAI28419227
040 $a MiAaPQ $c MiAaPQ
100 1 $a Peri, Prudhvi Ram. $3 3559221
245 1 0 $a Electron Microscopy Characterization of GaN-on-GaN Vertical Power Devices = $b Electron Microscopy Characterization of GaN-on-GaN Vertical Power Devices .
260 1 $a Ann Arbor : $b ProQuest Dissertations & Theses, $c 2021
300 $a 129 p.
500 $a Source: Dissertations Abstracts International, Volume: 82-11, Section: B.
500 $a Advisor: Smith, David J.
502 $a Thesis (Ph.D.)--Arizona State University, 2021.
506 $a This item must not be sold to any third party vendors.
520 $a Wide bandgap semiconductors are of much current interest due to their superior electrical properties. This dissertation describes electron microscopy characterization of GaN-on-GaN structures for high-power vertical device applications. Unintentionally-doped (UID) GaN layers grown homoepitaxially via metal-organic chemical vapor deposition on freestanding GaN substrates, were subjected to dry etching, and layers of UID-GaN/p-GaN were over-grown. The as-grown and regrown heterostructures were examined in cross-section using transmission electron microscopy (TEM). Two different etching treatments, fast-etch-only and multiple etches with decreasing power, were employed. The fast-etch-only devices showed GaN-on-GaN interface at etched location, and low device breakdown voltages were measured (~ 45-95V). In comparison, no interfaces were visible after multiple etching steps, and the corresponding breakdown voltages were much higher (~1200-1270V). These results emphasized importance of optimizing surface etching techniques for avoiding degraded device performance. The morphology of GaN-on-GaN devices after reverse-bias electrical stressing to breakdown was investigated. All failed devices had irreversible structural damage, showing large surface craters (~15-35 microns deep) with lengthy surface cracks. Cross-sectional TEM of failed devices showed high densities of threading dislocations (TDs) around the cracks and near crater surfaces. Progressive ion-milling across damaged devices revealed high densities of TDs and the presence of voids beneath cracks: these features were not observed in unstressed devices. The morphology of GaN substrates grown by hydride vapor-phase epitaxy (HVPE) and by ammonothermal methods were correlated with reverse-bias results. HVPE substrates showed arrays of surface features when observed by X-ray topography (XRT). All fabricated devices that overlapped with these features had typical reverse-bias voltages less than 100V at a leakage current limit of 10-6 A. In contrast, devices not overlapping with such features reached voltages greater than 300V. After etching, HVPE substrate surfaces showed defect clusters and macro-pits, whereas XRT images of ammonothermal substrate revealed no visible features. However, some devices fabricated on ammonothermal substrate failed at low voltages. Devices on HVPE and ammonothermal substrates with low breakdown voltages showed crater-like surface damage and revealed TDs (~25µm deep) and voids; such features were not observed in devices reaching higher voltages. These results should assist in developing protocols to fabricate reliable high-voltage devices.
590 $a School code: 0010.
650 4 $a Electrical engineering. $3 649834
650 4 $a Materials science. $3 543314
650 4 $a Civil engineering. $3 860360
650 4 $a Molecular chemistry. $3 1071612
653 $a Defects
653 $a Electron microscopy
653 $a Focused ion beam
653 $a Gallium nitride
653 $a III-V materials
653 $a Semiconductors
653 $a Electrical stressing
653 $a Heterostructures
653 $a Etching
653 $a Breakdown voltage
653 $a High power devices
690 $a 0794
690 $a 0544
690 $a 0543
690 $a 0431
710 2 $a Arizona State University. $b Materials Science and Engineering. $3 1680702
773 0 $t Dissertations Abstracts International $g 82-11B.
790 $a 0010
791 $a Ph.D.
792 $a 2021
793 $a English
856 4 0 $u https://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=28419227