Epitaxial Growth of Mg_xCa_1–xO on GaN by Atomic Layer Deposition

Abstract

Abstract:We demonstrate for the first time that a single-crystalline epitaxial Si-based power devices could not meet these demands due to the small band gap (1.1 eV) and low breakdown field of Si. 2 GaN could replace Si for future power applications because of its higher band gap (3.4eV) and higher breakdown field. One powerful method to examine the epitaxial film quality is cross-sectional TEM imaging. GaN. The well-defined film spots in the diffraction pattern (Fig. S2) peaks are seen in all three samples (Fig. 3 a). The absence of MgO and CaO peaks indicates that phase separation into the two binaries has not occurred. The A "top-to-top" capacitor structure was used to measure the capacitance due to the insulating sapphire substrate under the GaN (Fig. S3). In this measurement, the positive probe is placed in contact with the gate electrode while the negative probe is in contact with the large area of GaN covered by aluminum metal. Since the gate has a serial connection with the large area, the measured capacitance is given by, where m C is the capacitance measured by the LCR meter, g C is the capacitance of the gate and l C is the capacitance of the larger area. Since C l >> C g , the measured capacitance is dominated by the gate: m g C C .The measured room temperature and high temperature CV curves from three Mg x Ca 1-x O /GaN samples as well as an Al 2 O 3 /GaN sample are summarized in Fig. 4.In room temperature studies (Fig. 4 a, b and c there is a 20% dispersion in the same region in the Al 2 O 3 /GaN sample (Fig. 4 d) 20 The detailed measurement procedure and conductance data are summarized in the supporting information (Fig. S5). 18 The measured values of D it are summarized in Fig. 4 i. Two of the samples with epitaxial films show the lowest D it

From the source: student-centred guest lecturing in a chemical crystallography class

“…The focus placed on the 'source' of advanced crystallography techniques allows students to learn what crystallography can do for their research and to network with professionals who can potentially provide a valuable collaboration. Students are typically keen to take advantage of such resources once they become available and apply what they have learned to complete their research projects (Das et al, 2017;Feng et al, 2017;Hwang et al, 2015;Lou et al, 2016;Powers et al, 2013Powers et al, , 2016Powers, Anderson et al, 2014;Ramadhar et al, 2015aRamadhar et al, ,b, 2017. A list of example beam time proposals that students submitted for their own research projects at two major user research facilities can be found in Table S1 in the supporting information.…”

New insights towards strikingly improved room temperature ethanol sensing properties of p-type Ce-doped SnO2 sensors

“…The increase in magnitude of lattice parameter and cell volume of Ce doped SnO 2 are shown in Table 1 . The lattice parameter ‘a’ and ‘c’ of the Ce doped SnO 2 unit cell is found to increase linearly with the Ce concentration following Vegards law 39 , 40 which is shown in figure (see Supporting Information, Fig. S1 ).…”

Partially Crystallized Ultrathin Interfaces between GaN and SiNx Grown by Low-Pressure Chemical Vapor Deposition and Interface Editing

“…The growth and development of high-quality dielectrics is of exceptional importance for their incorporation into next-generation GaN high-electron-mobility transistors (HEMTs) because of their great potential in the radio frequency and power switching applications for both lateral and vertical devices. , The high-quality interface and the high tolerance to the electric stress are the main criteria and underlying challenges to both the material selection and growth. Various materials have been adopted on the (Al)­GaN surface as the passivation and gate dielectric layer to improve the device performance and reliability, such as SiO 2 , SiN x , , AlN, Al 2 O 3 , AlON, , HfO 2 , ZrO 2 , MgGaO, and AlSiO . Among them, SiN x dielectrics grown by low-pressure chemical vapor deposition (LPCVD) demonstrated excellent time-dependent dielectric breakdown (TDDB) properties in GaN MIS-HEMT .…”

“…1,2 The high-quality interface and the high tolerance to the electric stress are the main criteria and underlying challenges to both the material selection and growth. Various materials have been adopted on the (Al)GaN surface as the passivation and gate dielectric layer to improve the device performance and reliability, such as SiO 2 , 3 SiN x , 4,5 AlN, 6 Al 2 O 3 , 7 AlON, 8,9 HfO 2 , 10 ZrO 2 , 11 MgGaO, 12 and AlSiO. 1 Among them, SiN x dielectrics grown by low-pressure chemical vapor deposition (LPCVD) demonstrated excellent timedependent dielectric breakdown (TDDB) properties in GaN MIS-HEMT.…”