Three-dimensional diamond MPCVD growth over MESA structures: A

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Three-dimensional diamond MPCVD growth over MESA structures: A geometric model for growth sector configuration Fernando Lloret, Daniel Araujo, David Eon, and Etienne Bustarret Cryst. Growth Des., Just Accepted Manuscript • DOI: 10.1021/acs.cgd.8b01424 • Publication Date (Web): 12 Nov 2018 Downloaded from http://pubs.acs.org on November 13, 2018

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Crystal Growth & Design

Three-dimensional diamond MPCVD growth over MESA structures: A geometric model for growth sector configuration Fernando Lloret†,‡,*, Daniel Araújo‡, David Eon§, and Etienne Bustarret§

†

Institute for Material Research, Hasselt University, 3590, Diepenbeek, Belgium

†

‡

IMOMEC, IMEC vzw, 3590, Diepenbeek, Belgium

Dpto. Ciencia de los Materiales, Universidad de Cádiz, 11510 Puerto Real (Cádiz), Spain

§

Univ. Grenoble Alpes, CNRS, Institut Néel, 38000 Grenoble, France

ABSTRACT The overgrowth of {100}-oriented patterned diamond substrates by microwave plasma enhanced chemical vapor deposition (MPCVD) was studied by

ACS Paragon Plus Environment

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Crystal Growth & Design 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

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transmission electron microscopy (TEM) through a stratigraphic approach. A sector-like growth behavior is evidenced, resulting from a competition between slowly growing facets at protruding (top) corners and edges against quickly growing facets at recessing (bottom) corners. Depending on the pattern orientation and height, under some particular experimental conditions, it is possible to predict the sequence of growth sectors, and thus to choose the crystallographic orientation of the overgrown surface, by stopping the growth at the right stage. A simple two-dimensional model is provided allowing to fabricate structures adapted to the requirements of specific electronic devices.

Introduction Silicon based devices are still the most advanced and mature for power applications. However, wide band gap materials (WBGM)-based devices should enhance the energy efficiency in industrial-scale power electronics and clean energy technologies because of their superior electrical and thermal properties.1


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For this reason, WBGMs have been seriously considered for such applications since the 1980s and are now beginning to be used commercially.2 Among WBGM, diamond stands out : the excellent mobility of electrons and holes, 4500 cm2V1s-1

and 3800 cm2V-1s-1 respectively, allows high current densities, while the high

thermal conductivity enhances the heat dissipation capability, both key parameters in power electronics.3 In addition, its high breakdown voltage, the best among the semiconductors materials (10MV/cm), makes it very attractive for high voltage applications. Consequently, diamond growth techniques and diamond-based devices have been widely investigated over the last two decades. Great progress has been obtained in the design and fabrication of several diamond-based devices such as bipolar and junction field effect transistors, Schottky-pn diodes and Schottky diodes.4-10 This last one, with up to 10KV breakdown voltages, is the main exponent of diamond as the best candidate for power electronics. Moreover, the use of three-dimensional designs has been proposed as the best way to achieve commercial diamond based devices since, through them, the serial resistance of the active layer is minimized, contacts can be more freely designed


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to reduce the high electric fields, growth sectors in which incorporation of dopants is promoted

can be favoring, and the generation of so-called killer defects can

be avoided controlling and deviating dislocations to improve the performance.11-14 In addition, alternative geometries also favor the miniaturization. In this context, selective growth was demonstrated to be a powerful method to develop threedimensional and other unusual geometries.15 Homoepitaxial diamond growth mechanisms by microwave plasma chemical vapor deposition (MPCVD) or at high-pressure and high-temperature (HPHT) have been largely studied and the models developed are well known and accepted.16-21 These models are mainly based on the relative growth velocities of four low index crystal planes: {100}, {110}, {111} and {113}. The value of the velocity ratios, i.e. the so-called growth parameters, describing the global morphology of the crystal during the growth process, allow to predict the final shape of the macroscopic crystal. This final shape is determined by the slowest growing facets sharing a protruding edge that limits the growth.16,18,19 Nevertheless, due to difficulties in their structural characterization, growth mechanisms at the nm-scale


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remain largely unknown. In order to establish the phenomena involved in such non-planar growth and to tentatively model the growth, we propose to study the intermediate stages of non-faceted or planarized overgrown diamond structures by an approach that involves heavily doped nm-thick sublayers used as time markers in a stratigraphic configuration that has been described elsewhere.22 This technique is here used to determine the relative influence of the size and the geometrical singularities introduced by the mesa structures on the overgrowth of diamond mesa patterned substrates.

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Experimental Section To carry out this study, three {100}-oriented HPHT diamond substrates were patterned by laser lithography with circles of aluminum deposited by electron beam evaporator in a high-vacuum chamber. Samples were etched into mesa disk patterns by inductively coupled plasma reactive ion etching (ICP-RIE) using pure oxygen gas. Mesa disks were five micrometers in diameter and 0.9 µm (#A), 1.7 µm (#B) and 2.7 µm (#C) in height. Samples were then overgrown by microwave plasma enhanced chemical vapor deposition (MPCVD) using a NIRIM


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type reactor. Different stacks of doped/undoped bilayers were grown over the patterned substrate using for the doped layers 0.25% of methane diluted in hydrogen and, for sample #A, 10700 ppm of diborane over methane and for #B and #C 28000 ppm. In all samples the undoped layers were grown with 0.1% of CH4/H2. No oxygen was used during the growth of any of these samples. Pressure and temperature were set at 33 Torr and 900oC, respectively. Bilayers number and times of growth varied for each sample: Sample #A had 13 doped/undoped bilayers of 2 and 60 minutes each. Sample #B involved 6 doped/undoped bilayers of 5 and 60 minutes. And sample #C consisted in only one doped/undoped bilayer of 8 minutes and 180 minutes. Consequently, times of growth were different leading to different thicknesses. Samples have been studied by transmission electron microscopy (TEM) using a JEOL 2100 microscope. Electron transparent lamellas were made by lift-out method by focused ion beam (FIB) with a Dual Beam FEI QUANTA 200 3D24. Profilometry analysis was carried out using a 3D Z-300 profilometer. Results and Discussion


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Growth conditions were chosen to promote the growth along the lateral directions, considering such directions as the ones different from the perpendicular to the initial diamond substrate, i.e. along {100}.23 Heavily doped nm-thick sublayers work as time markers in a such a stratigraphic configuration. Such layers, which are easily distinguishable by transmission electron microscopy in conventional diffraction mode (CTEM), act as milestones of the growth plane orientation as growth proceeds.22,25 In this context, growth orientations are determined easily by measuring the misorientation of the doped layers respect to the {100} orientation of the initial substrate surface. Figures 1 (a) and (b) show this stratigraphy study performed on sample #A. They confirm that growth proceeds by growth sectors in a way similar to that in HPHT diamond growth. Such sectors change along the growth process in an obvious tendency toward planarization due to the excellent wetting properties inherent to homepitaxial growth.


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(c)

(b) (a)

(c)

(b) (a) 5µm

Figure 1. (a) TEM cross section micrograph of sample #A oriented on the (001) pole. (b) TEM cross section micrograph of the same sample oriented on the (011) pole. Doped layers are visible as dark contrast lines marking the regions of growth with the same orientations. These regions are highlighted by colors and labelled with the corresponding orientation using the same color. Platinum observed and marked by Pt is due to the FIB-lamella preparation. (c) SEM


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micrograph of the corresponding mesa disk overgrowth. Dashed white circle mark the estimated initial mesa etched disk and dashed white lines the lamellas extracted showed in (a) and (b). Regions colored with the same color correspond to regions tilted the same angle respect to the bottom of the sample (it is (100) plane) measured by profilometry.

This implies different growth rates for the vertical and in-plane expansion of the overgrown material, generating additional strain at edges and corners. Moreover, lateral growth fronts originating in neighboring mesa patterns will coalesce at some point, leading to a planarization of the structure that precludes a straightforward a posteriori sector shape analysis. Based on the growth timesheet and on the diamond thickness separating doped layers, growth rates have been calculated for each orientation. They are displayed on table 1, where and nearby orientations are observed to be the slowest. In contrast, the more lateral the growth direction, the faster the growth ( directions are the fastest). Both very fast growth orientations and much slower ones are seen to be present.


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Table 1. Growth rates (in nm/min) of facets with different crystallographic orientations calculated from the spacing of doping superlattices observed in sample #A. Equivalent growth orientations are grouped by shaded/unshaded columns.

[3 1 1] [3 1 0] [2 1 1] [2 1 0] [1 1 0] [1 11 11][1 11 0] [1 0 0 ] [3 2 0] [5 1 0] [1 50 0] 6

3

8

10

14

2

2

1

13

7

2

Figure 1 (c) shows a SEM micrographs of the mesa disk overgrown with a cross-like final shape. These facets have been obtained by optical profilometry. The equivalent planes, sharing the same misorientation with respect to the [100], are identified by the same color. This study reveals [310] and [1 11 0] orientations observed on figure 1 (a) as projections of [311] and [1 11 11] orientations on the (001) plane (figure 1 (b)). Growth is then only carried out through the two perpendicular axes of the cross that the overgrown disk seems to form, i.e., and directions.


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It is obvious that the plane of growth conditions the process because of the chemical restrictions that it implies (mainly due to the superficial free energy). However, in the case of mesa patterned substrates, there are corners that act as geometrical singularities and introduce physical restrictions to the growth process that also reduce the degrees of freedom. Sample #B and #C have been grown specifically to study the influence of the corner. The main difference between the three samples is the height of the initial mesa disk (resulting from the etched depth, and governing the distance between the upper edge and the bottom corner). Figure 2 shows TEM micrographs of the three samples. Figure 2 (a) corresponds to a cross section view of sample #B where the two growth orientation regions observed are colored and labelled with their corresponding planes. By comparing with Figure 1 (b), sample #B exhibit the same final facet than three microns grown of sample #A. Figure 2 (b) shows a cross section view of the equivalent region of sample #C. Thanks to the stratigraphic approach, orientations followed during the first steps are shown to be quite similar. Using the same color codes


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for the same growth orientations, the sectors look similar independently of the height of the mesa disk, and the slowest velocities {100} do not determine the shape of the overgrown patterns.

Figure 2. Cross sectional TEM micrograph of samples (a) #B and (b) #C. Micrographs have their growth orientation marked by colors and identified with labels. (c)Resulted schematic of the growth sectors and final shape for a generic height, H, with the corresponding to samples #A, #B and #C superimposed.

To evaluate the growth independently from the height of the mesa disk, the resulting schematics of the growth sectors in the three samples have been


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rescaled and superimposed (figure 2 (c)). Growth sectors are proved to be the same in all cases, but their size depends on the height of the mesa disk. (a)

t1

(b)

t5

(c)

t10

(d)

t15

(e)

[2 1] [1 0] [1 1]

FIG. 3. Two-dimensional simulation model of the formation of the growth sectors. Four different growth velocities and orientations have been considered. (a) First step of the growth after an arbitrary time t1. (b) Shape of mesa disk after a t5, equal to 5 times t1. Lines corresponding with each t are drawn with a different color. (c) Shape of mesa disk after a t10, moment in which one of the growth


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orientations [1 0] disappears due to the convergence of other two ([2 1] and [1 1]). (d) Tendency of the growth after t15 with the changes on the size of the growth sectors. (e) Situation of the mesa structure after t15 time of growth in which each growth sector is colored with a different color in according to their orientation of growth, i.e. region grown along the [21] direction is colored green, along the [10] is colored purple and along the [11] is colored red.

To explain the role of the edges and corners in the generation of these unusual growth sectors, a simple two-dimensional model is presented in figure 3. In this model, four different growth velocities and orientations are considered based on the results observed in the TEM micrographs. Due to the model is simulated in two dimensions, the growth orientations chosen were [1 0], [0 1], [2 1] and [1 1] with of 1, 0.1, 0.7 and 1.4 A.U. velocities, respectively. Figure 3 shows four different times corresponding to t1, t5, t10 and t15. Each colored line represents an arbitrary time ti as doped layer represented in the TEM micrographs. The initial disk is drawn by a thicker blue color line and only one of the disk sides is shown. Figure 3 (a), simulates the lateral growth after a time t1, in which the


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shape of the mesa structure is modified. On the outer corner, the [2 1] orientation governs the growth and the resulting shape: it is not the slowest but it is slowest along the [0 1]. The other orientations cannot be physically supported so that they do not contribute to the growth. This situation is usually observed during CVD diamond crystal growth16,18,19. On the other hand, the shape evolution of the inner corner at the foot of the mesa is governed by the fastest growth direction, [1 1]. Indeed, thanks to the two adjacent planes forming the initial corner, there is a physical support for this fast orientation. This particular situation yields the unusual growth sectors sequence observed experimentally as described above, in which fast growing sectors occur, starting from the bottom corner and provide the fast growth sectors observed. Such a behavior is maintained throughout the following steps (figure 3 (b)) enlarging the [2 1] and [1 1] growth sectors at the expense of the [1 0] one and changing the shape of the initial mesa disk. After a while, [2 1] (slow) and [1 1] (fast) growth orientations take over, and the intermediate [1 0] orientation


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completely disappear. This situation is displayed on figure 3 (c). From this moment, growth sectors are reduced to three: [2 1], [1 1] and [0 1]. Over the next growth steps, [2 1]-oriented facets will limit the growth rate and govern the pattern shape, now at the expense of the [1 1] sector (figure 3 (d)) that presumably will also disappear. The schematics finally obtained are quite similar to those observed by TEM, i.e., a growth sequence with the coexistence of different orientations in which the slowest plane does not govern the growth from the beginning (figure 3 (e)). The overgrowth of patterned substrates leads then to the coexistence of different growth planes at the same time. The stratigraphic study showed that these planes change along the growth thickness, leading to a planarization. The speed of this planarization process will depend on the height of the mesa structure. Conclusions From this study, it can be concluded that, keeping the same growth conditions, the growth sectors will be the same, i.e. the 3D overgrowth process is reproducible. Moreover, the height of the mesa structure will define the time


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sequence of the growth sectors. This allows to select patterns that will lead to a specifically oriented facet over a certain period of time. In this way, it is possible to predict the growth orientation at different times of the growth process and for different mesa sizes. Consequently, particular orientations and growth durations maybe be chosen to obtain a particular final shape suited to the purpose and design of high performance electronic devices.

AUTHOR INFORMATION Corresponding Author *Fernando Lloret, [email protected]

Author Contributions The manuscript was written through contributions of all authors. All authors have given approval to the final version of the manuscript.

Funding Sources


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This work was funded through grants from the Spanish Ministry of Economy and Competitiveness (TEC2014-54357-C2-2-R, HiVolt-nano project) and from the European H2020 Program (SEP-210184415, GreenDiamond project).

ACKNOWLEDGMENT

This work was funded through grants from the Spanish Ministry of Economy and Competitiveness (TEC2014-54357-C2-2-R, HiVolt-nano project, and TEC201786102-C2-2-R, DIANMOS project) and from the European H2020 Program (SEP210184415, GreenDiamond project).

REFERENCES (1) Ozpineci, B.; Tolbert, L.; Smaller, faster and tougher, IEEE Spectrum, 2011,

48, 44-65. (2) Baliga, B.J.; Semiconductors for high-voltage, vertical channel field-effect transistors, J. Appl. Phys. 1982, 53, 1759-1764, DOI: 10.1063/1.331646. (3) Evans, D.A.; Roberts, O. R.; Williams, G.T.; Vearey-Roberts, A.R.; Bain, F.; Evans, S.; Langstaff, D.P.; Twitchen, D.J.; Diamond-metal contacts: interface


18

Page 19 of 26 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


barriers and real-time characterization, J. Phys. Condens. Matter. 2009, 21, 364223 DOI: 10.1088/0953-8984/21/36/364223.

(4) Kato, H; Oyama, K; Makino, T.; Ogura, M.; Takeuchi, D.; Yamasaki, S.; Diamond bipolar junction transistor device with phosphorus-doped diamond base layer, Diam. Relat. Mater. 2012, 27, 19-22, DOI: 10.1016/j.diamond.2012.05.004. (5) Iwasaki, T.; Hoshino, Y.; Tsuzuki, K.;. Kato, H; Makino, T.; Ogura, M.; Takeuchi, D.; Matsumoto, T.; Okushi, H.; Yamasaki, S.; Hatano, M.; Diamond junction field-effect transistors with selectively grown n(+)- side gates, Appl. Phys.

Express 2012, 5, 091301, DOI: 10.1143/APEX.5.091301. (6) Makino, T.; Tanimoto, S.; Hayashi, Y.; Kato, H.; Tokuda, N.; Ogura, M.; Takeuchi, D.; Oyama, K.; Ohashi, H.; Okushi, H.; Yamasaki, S.; Diamond Schottky-pn diode with high forward current density and fast switching operation,

Appl. Phys. Lett. 2009, 94, 262101, DOI: 10.1063/1.3159837. (7) Butler, J.E.; Geis, M. W.; Krohn, K.E.; Lawless Jr., J.; Deneault, S.; Lyszczarz, T.M.; Flechtner, D.; Wright, R.; Exceptionally high voltage Schottky


19


Page 20 of 26

diamond diodes and low boron doping, Semicond. Sci. Technol. 2003, 18, S67S71, DOI: 10.1088/0268-1242/18/3/309.

(8) Volpe, P-N.; Muret, P.; Pernot, J.; Omnès, F.; Teraji, T.; Koide, Y.; Jomard, F.; Planson, D.; Brosselard, P.; Dheilly, N.; Vergne, B.; Scharnholz, S.; Extreme dielectric strength in boron doped homoepitaxial diamond, Appl. Phys. Lett., 2010,

97, 223501, DOI: 10.1063/1.3520140. (9) Umezawa, H.; Kato, Y.; Omega on-resistance diamond vertical-Schottky barrier diode operated at 250 degrees C, Appl- Phys. Express, 2013, 6, 011302, DOI: 10.7567/APEX.6.011302.

(10) Traoré, A.; Muret, P.; Fiori, A.; Eon, E.; Gheeraert, E.; Pernot, J.; Zr/oxidized diamond interface for high power Schottky diodes, Appl. Phys. Lett., 2014, 104, 052105, DOI: 10.1063/1.4864060. (11) Tallaire, A.; Brinza, O.; Mille, V.; William, L.; Achard, J.; Reduction of dislocations in single crystal diamond by lateral growth over macroscopic hole,

Adv. Mater, 2017, 29, 1604823, DOI: 10.1002/adma.201604823.


20

Page 21 of 26 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


(12) Sato, K.; Iwasaki, T.; Hoshino, Y.; Kato, H.; Makino, T.; Ogura, M.; Yamasaki, S.; Nakamura, S.; Ichikawa, K.; Sawabe, A.; Hatano, M., Analysis of selective growth of n-type diamond in lateral p-n junction diodes by cross-sectional transmission electron microscopy, Jap. J. Appl. Phys., 2014, 53, 05FP01, DOI: 10.7567/JJAP.53.05FP01.

(13) Ushizawa, K.; Watanabe, K.; Ando, T.; Sakaguchi, I.; Nishitani-Gamo, M.; Sato, Y.; Kanda, H. Boron concentration dependence of Raman spectra on {100} and {111} facets of B- doped CVD diamond. Diamond Relat. Mater. 1998, 7, 1719, DOI: 10.1016/S0925-9635(98)00296-9.

(14) Lloret, F.; Gutierrez, M.; Araujo, D.; Eon, D.; Bustarret, E.; MPCVD Diamond lateral growth through microterraces to reduce threading dislocations density, Phys. Stat. Solidi A, 2017, 214, 1700242, DOI: 10.1002/pssa.201700242.

(15) Iwasaki, T.; Yaita, J.; Kato, H.; Makino, T.; Ogura, M.; Takeuchi, D.; Okushi, H.; Yamasaki, S.; Hatano, M.; 600 V Diamond Junction Field-Effect Transistors


21


Operated

at

200

°C,

IEEE

Electron

Device

Page 22 of 26

Lett.

2014,

35,

241,

DOI:

10.1109/LED.2013.2294969.

(16) Wild, C.; Kohl, R.; Herres, N.; Müller-Sebert, W.; Koidl, P.; Oriented CVD diamond films: twin formation, structure and morphology, Diam. Relat. Mater. 1994, 3, 373-381 DOI: 10.1016/0925-9635(94)90188-0. (17) Battaile, C.C.; Srolovitz, D.J.; Butler, J.E.; Atomic-scale simulations of chemical vapor deposition on flat and vertical diamond substrates, J. Cryst.

Growth, 1998, 194, 353-368, DOI: 10.1016/S0022-0248(98)00685-X. (18) Silva, F.; Achard, J.; Bonnin, X.; Michau, A.; Tallaire, A.; Brinza, O.; Gicquel, A.; 3D crystal growth model for understanding the role of plasma pre-treatment on CVD diamond crystal shape, Phys. Status Solidi A, 2006, 203, 3049-3055, DOI: 10.1002/pssa.200671101.

(19) Silva, F.; Bonnin, X.; Achard, J.; Brinza, O.; Michau, A.; Gicquel, A.; Geometric

modeling

of

homoepitaxial

CVD


diamond

growth:

I.

The

22

Page 23 of 26 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


{100}{111}{110}{113} system, J. Cryst. Growth, 2008, 310, 187-204, DOI: 10.1016/j.jcrysgro.2007.09.044.

(20) Tallaire, A.; Achard, J.; Brinza, O.; Mille, V.; Naamoun, M.; Silva, F.; Gicquel, A.; Growth strategy for controlling dislocation densities and crystal morphologies of single crystal diamond by using pyramidal-shape substrates,

Diam. Relat. Mater. 2013, 33, 71-77, DOI: 10.1016/j.diamond.2013.01.006. (21) Bogatskiy, A.; Butler, J.E.; A geometric model of growth for cubic crystal: Diamond

Diam.

Relat.

Mater.,

2015,

53,

58-65

DOI:

10.1016/j.diamond.2014.12.010.

(22) Lloret, F.; Fiori, A.; Araujo, D.; Eon, D.; Villar, M.P.; Bustarret, E.; Stratigraphy of a diamond epitaxial three-dimensional overgrowth using doping superlattices, Appl. Phys. Lett. 2016, 108, 181901, DOI: 10.1063/1.4948373. (23) F. Lloret, D. Araujo, D. Eon, M. P. Villar, J-M. Gonzalez-Leal, and E. Bustarret, Influence of methane concentration on MPCVD overgrowth of 100-


23


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oriented etched diamond substrates, Phys. Stat. Solidi A, 2016, 213, 2570-2574, DOI: 10.1002/pssa.201600182.

(24) Sugiyama, M.; Sigesato, G. A review of focused ion beam technology and its applications in transmission electron microscopy. J. Electron Microsc. 2004, 53, 527–536, DOI: 10.1093/jmicro/dfh071.  

(25) Araújo, D.; Alegre, M.P.; García, A.J.; Villar, M.P.; Bustarret, E.; Achatz, P.; Volpe, P.N.; Omnès, F.; Cross sectional evaluation of boron doping and defect distribution in homoepitaxial diamond layers, Phys, Status Solidi C, 2011, 8, 1366, DOI: 10.1002/pssc.201083991.


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For Table of Contents Use Only

Three-dimensional diamond MPCVD growth over MESA structures: A geometric model for growth sector configuration

Fernando Lloret, Daniel Araújo, David Eon, and Etienne Bustarret

The overgrowth of {100}-oriented patterned diamond substrates was studied by transmission electron microscopy through a stratigraphic approach. A sector-like growth behavior is evidenced, resulting from a competition between slowly growing facets at protruding (top) corners and edges against quickly growing facets at recessing (bottom) corners. Depending on the pattern orientation and height, it is


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possible to predict the sequence of growth sectors. A simple two-dimensional model allows to fabricate specific diamond structures.


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Three-dimensional diamond MPCVD growth over MESA structures: A

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