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Correlations of Electronic Interface States and Interface Chemistry on Dielectric/III Nitride Heterostructures for Device Applications

Jackson, Christine M
http://orcid.org/0000-0002-8119-4593
http://rave.ohiolink.edu/etdc/view?acc_num=osu15257361319909

Abstract Details

2018, Doctor of Philosophy, Ohio State University, Electrical and Computer Engineering.
AlGaN/GaN high electron mobility transistors (HEMTs) and other devices that take advantage of the particular material properties of the III-nitride material system have become important for a range of applications, including high frequency and high voltage electronics. A crucial approach for further improvement of these devices has been the addition of dielectric layers. Successful implementation of these newer device designs relies on understanding the nature and impact of specific defects present within semiconductor layers, and at interfaces between such materials. Crystallographic defects influence electronic and optical material properties, as well as the entire behavior of devices in their intended application. For instance, defects at the interface of insulators and III-nitrides in HEMTs can seriously degrade electron mobility and increase device switching response times, preventing the devices from operating effectively at the target power and frequency. Interface defect states that respond to electrical signals, through the capture or emission of electrons, are quantified as the interface state defect density (Dit). This Dit is inherently related to the chemistry of an interface and has proven very difficult to quantify in a manner specific to individual defect states and physical sources. With the implementation of GaN-based electronics in so many commercial and government applications, advancing the understanding of interface states related to GaN HEMTs has been one of the major goals of the field over the last decade. With this motivation, this dissertation applies a unique combination of techniques to this problem, notably constant capacitance deep level optical spectroscopy (CC-DLOS) and deep level transient spectroscopy (CC-DLTS), with internal photoemission (IPE) and X-ray photoelectron spectroscopy (XPS). The objective is to link electronic details of interface state distributions with local chemical information as a function of systematic variations in interface design for a range of material combinations between insulators onto controlled III-nitride surfaces. Atomic layer deposited (ALD) dielectrics are the main focus of this study, due to the expected ideal nature of the ALD processes. Here, special attention is paid to ALD Al2O3. As-deposited ALD Al2O3 layers were first characterized to demonstrate the electrical characterization techniques and provide a baseline for comparison. Chemical and electrical changes at the Al2O3/GaN interface were considered in relation to post-deposition annealing processes and pre-deposition surface treatments. Concentrations of H, C, and F near the interface correlated with differences in Dit. Other ALD dielectrics were also characterized and differences in Dit suggested that the Al2O3/GaN interface likely forms fewer active defect than other dielectric/GaN interfaces. With this conclusion in mind, bilayer dielectrics using Al2O3 interlayers were explored. However, these results suggested some unexpected interactions between the ALD layers, showing that the ALD process is not as simple as is often assumed.
Steven Ringel (Advisor)
Siddharth Rajan (Committee Member)
Tyler Grassman (Committee Member)
127 p.
Electrical Engineering; Engineering; Materials Science
semiconductor interfaces, electronic defects, atomic layer deposition, DLTS

Recommended Citations

Citations

  • Jackson, C. M. (2018). Correlations of Electronic Interface States and Interface Chemistry on Dielectric/III Nitride Heterostructures for Device Applications [Doctoral dissertation, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu15257361319909

    APA Style (7th edition)

  • Jackson, Christine. Correlations of Electronic Interface States and Interface Chemistry on Dielectric/III Nitride Heterostructures for Device Applications. 2018. Ohio State University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu15257361319909.

    MLA Style (8th edition)

  • Jackson, Christine. "Correlations of Electronic Interface States and Interface Chemistry on Dielectric/III Nitride Heterostructures for Device Applications." Doctoral dissertation, Ohio State University, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=osu15257361319909

    Chicago Manual of Style (17th edition)

osu15257361319909
263
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This open access ETD is published by The Ohio State University and OhioLINK.