The Influence Of Nitrous Oxide On Growth Of CVD Single Crystal Diamonds

Single crystal diamond attracted many researchers’ attention because of itsexcellent properties. However, limited by their size, doping and cost, natural andhigh-pressure high-temperature （HPHT） diamonds are unsuitable for applications.Single crystal diamond synthesized by MPCVD technique becomes the mostpromising method.In this work, nitrogen-and oxygen-related radicals was generally introduced inthe reaction atmosphere （H2：CH4=750sccm：90sccm） with different modalities（N₂，O2，N₂O） to synthesize homoepitaxy single crystal diamonds. The sampleswere tested by microscopy, optical emission spectroscopy （OES）, Raman,photoluminescence （PL），SEM and AFM.For an appropriate addition of N₂O （at2sccm）, the product presents the highestgrowth rate （135μm/h） and narrowest FWHM （2.59cm-1） of diamond Raman peak.Moreover, introducing N₂O can result in the density of the large-sized pits decrease onthe top surface of SCDs. These facts are expected to realize the long-term stabledeposition required for large crystals production. The surface roughness and color areboth in respect to the N-related content. The CVD SCDs grown with N₂O are of highquality, high growth rate, smooth surface, and/or enhanced transparency with respectto the products grown with the additions of N₂or O2. It is demonstrated that thecombined effect of N-and O-related radicals generating from N₂O in the CH4/H2plasma ambient is significant to achieve high quality and high-rate growth ofhomoepitaxial CVD SCDs.