ECR-PEMOCVD Low Temperature Growth Of GaN Thin Films On Copper Single Crystal Substrate

Gallium Nitride(Ga N) semiconductor light emitting diode(LED) the vast majority of the sapphire substrate(?-Al2O3),?-Al2O3 substrate has the disadvantages of expensive price, insulation, poor thermal conductivity, small size(only 2~4 inches in diameter). Compared with?-Al2O3 substrate, some metal substrates have the advantages of cheap, conductive, thermal conductivity, large area and high reflectivity, The metal substrate not only can be used directly as the electrode of LED, but also helps to improve the heat dissipation performance of the chip and the effect of the light reflection, thus greatly improving the LED brightness. In the self-supported all metal substrate, it is beneficial to the preparation of Ga N based LED with a vertical conductive structure, Can completely solve the problem of current crowding in the transverse conductive structure Ga N based LED prepared on?-Al2O3 and other insulating substrates, which can improve the power of LED and reduce the production cost of LED.From the progress of the domestic and foreign, the reports of Ga N based films grown on the self-supported metal substrates are very few. The main reason is that the growth temperature of conventional metal organic chemical vapor deposition(MOCVD) is about 1050 degrees. This makes a lot of metal substrate and Ga N based films produce harmful interface reaction, high temperature will not only accelerating metal particles to the diffusion of Ga N based film, will also increase between the Ga N based film and the metal substrate due to thermal expansion coefficient difference caused by thermal stress. Electron cyclotron resonance plasma enhanced metal organic chemical vapor deposition(ECR-PEMOCVD) low temperature growth method was used to grow a single c axis orientation of high quality Ga N thin film on the self-supported single crystal copper substrate. In ensuring the quality of the Ga N film at the same time, reduce the film growth temperature, The adverse reaction caused by the high temperature deposition process is effectively suppressed. so that the growth of the LED device thermal conductivity and electrical conductivity better, more excellent heat.Low temperature growth of Ga N on single crystal Cu, Using gallium(TMGa) as gallium source, nitrogen(N2) as a nitrogen source, Ga N thin films were formed by plasma acceleration and TMGa reaction and the Cu film was formed on the substrate, Focus on the control of buffer layer and TMGa epitaxial growth layer flow influence mechanism of Ga N film growth performance and the best optimization parameter. Using reflection high-energy particles(RHEED), X-ray diffraction(XRD), atomic force microscopy(AFM), photoluminescence spectra(PL spectra) and current voltage test(I-V test) and other characterization methods to analyze the crystal structure of Ga N films, surface morphology, optical properties and electrical properties. The deposition temperature is 300?buffer layer, the TMGa flow rate is 1.1sccm, Growth time 30 min;the deposition temperature is 450?, the growth layer, the TMGa flow rate is 1sccm Ga N,Growth time 3Hour. Ga N film quality is the best, which has better crystal quality and strong ultraviolet emission peak, and the contact characteristics between Ga N thin film and metal Cu is good ohmic contact.