Photon-assisted MOCVD growth of II-IV-N2, II-III2-IV-N4 semiconductors and their heterostructures with III-N
T2020-144 A novel photon-assisted MOCVD growth method to synthesize II-IV-N2 materials
Zn-IV-N2 and Mg-IV-N2 compounds have been reported to be synthesized by a number of techniques including chemical vapor deposition (CVD), vapor-liquid-solid (VLS) technique, ammonothermal synthesis, radio frequency (RF) sputtering, pulsed laser deposition, molecular beam epitaxy (MBE) and metalorganic chemical vapor deposition (MOCVD). In the case of the III-N alloys, MOCVD has been the most commonly adopted epitaxy technique by the industry, so it is a feasible path for developing high-quality II-IV-N2 as well as developing II-IV-N2 and III-N heterostructures.
One of the major challenges in epitaxy of Zn-IV-N2 and Mg-IV-N2 compounds stems from the low sticking coefficients of Zn and Mg. Sticking coefficients of atoms being adsorbed on to the growth surface depend on several factors including the condensation coefficients and adsorption life-time/desorption rate. Therefore, in order to achieve stoichiometric II-IV-N2 films by MOCVD, substrate temperature needs to be sufficiently low.
A team of researchers at The Ohio State University led by Dr. Hongping Zhao has developed a novel photon-assisted MOCVD growth method to synthesize II-IV-N2 materials, such as Zn-IV-N2, Mg-IV-N2, ZnGa2-IV-N4 and MgGa2-IV- N4, as well as III-N/II-IV-N2 heterostructures. The method implements a photon beam that be channeled in such a way that the incident photons will interact with the gas molecules above the substrate surface and can be controlled in order to adjust the interactions with the precursors. The II-IV-N2, II-III2-IV-N4, or their heterostructures with III-N will be deposited on a substrate (e.g., GaN, sapphire, GaN/sapphire, Si, and etc.) by using precursor materials (e.g., dimethylzinc (DMZn)/DEZn for Zn; Cp2Mg for Mg; SiH4 for Si; GeH4 for Ge; tetramethyltin (TMSn)/ tetraethyltin (TESn) for Sn; NH3 for N etc.) in an MOCVD chamber. Growth parameters including the reactor pressure and precursor flow rates will be selected to achieve high crystalline quality materials with optical and electrical transport properties, as well as low defect densities. The growth can be done in a single step or multiple steps.
This novel method of photon-assisted MOCVD growth of II-IV-N2, II-III2-IV-N4 semiconductors and their heterostructures with III-N can provide a new route to achieve high-quality materials for both optoelectronic and electronic devices.
- Optoelectronic material manufacturing
- High crystalline quality materials
- Low defect densities