Identification of Dislocations in Synthetic Chemically Vapor Deposited Diamond Single Crystals

Abstract

International audienceHigh purity chemically vapor deposited (CVD) diamond single crystals are now widely available. However, the reduction of dislocations in this material still remains an important challenge that will strongly condition its adoption in areas such as optics, electronics, and spintronics, where these defects have a disastrous effect on the properties. In this work we report on a methodology that allows a complete identification of the type, density, and distribution of dislocations in a high quality CVD single crystal. A good agreement between all characterization techniques was established. When the surface is adequately prepared, a simple plasma etching allows evidencing 2 main dislocation types: 45° mixed and edge, with the latter one being dominant with a density of around 4.5 × 104 cm–2. This investigation paves the way to the development of a quick and simple process to analyze dislocations toward getting a better understanding of their impact on the material properties and eventually elaborating strategies to eliminate them

Toward High‐Performance Diamond Electronics: Control and Annihilation of Dislocation Propagation by Metal‐Assisted Termination

“…Inverted pyramidal shapes with one side of the square pit aligned to the <110> direction were observed. These are typical etch‐pit shapes that originate from dislocations . As shown in Figure d, the substrate displayed an etch‐pit density of 2 × 10 6 cm −2 , which is consistent with the spot density of Band‐A.…”

Detection of Defects in Diamond by Etch‐Pit Formation

“…Deep depth point‐bottom etch pits correspond to 45° mix dislocation. Shallow depth point‐bottom etch pits correspond to edge dislocation . Origins of the flat‐bottom pit is thought to be dislocation or microfractures introduced by polishing .…”

“…Several researchers have reported etch‐pit formation of diamond. They formed etch pits using hydrogen or hydrogen/oxygen (H 2 /O 2 ) plasma . Studies showing correlation between electric properties of diamond and etch‐pit features are scarce .…”

Reduction of Dislocations in Single Crystal Diamond by Lateral Growth over a Macroscopic Hole

“…[28] A network of inclined dislocations have also been obtained recently by growing on a [110]-oriented substrate. [10] In parallel to these improvements, the presence of extended defects such as threading dislocations (TDs) is the focus of increasing attention [11][12][13] in a similar way to what happened decades ago with other semiconductor materials such as SiC or GaN. It consists of filtering dislocations by growing laterally from a homo-or heterosubstrate that is partly covered by an appropriate mask.…”

“…These efforts were mostly driven by highly promising applications in electronics such as power diodes and transistors, [3] optics for X-ray [4] and Raman lasers, [5] high-energy particle detectors [6] as well as magnetic sensors, [7] and quantum information processing devices [8,9] based on the properties of luminescent centers. [10] In parallel to these improvements, the presence of extended defects such as threading dislocations (TDs) is the focus of increasing attention [11][12][13] in a similar way to what happened decades ago with other semiconductor materials such as SiC or GaN. Synthetic diamonds that outperform their natural counterparts can now be produced in a reproducible way and with an unprecedentedly low impurity content, down to the parts per trillion range for the best CVD crystals.…”