Font Size: a A A

Investigation Of Growth Of Gallium Nitride Thin Films On Silicon And UV Photodetector

Posted on:2003-10-06Degree:DoctorType:Dissertation
Country:ChinaCandidate:H X ZhangFull Text:PDF
Abstract/Summary:PDF Full Text Request
In recent years, Gallium Nitride as a wide band gap semiconductor has attracted more and more attention and advanced rapidly, mainly due to its promising applications in short-wave light-emitting devices, photodetectors, as well as anti- radiation, high frequency and high power electronic devices. Up to date, it is still very hard to grow GaN bulk crystals, so the heteroepitaxial growth of high quality GaN thin films is the premise for the development of GaN-based devices. Sapphire is the most commonly used substrate for the GaN epitaxy. But sapphire itself is not conductive and also hard to cleave. Silicon, as the most important semiconductor material, should be another promising substrate for GaN. Compared with sapphire, silicon is readily available in larger size, lower cost and also conductive. What is more attractive, the epitaxy of GaN on silicon substrates can potentially combine optoelectronic properties of GaN with highly advanced silicon electronic devices. Therefore, the investigation of GaN epitaxy on silicon is of extreme practical importance. In this paper, we first presented a comprehensive review of the research history and current status of GaN material preparation and GaN-based devices processing. On the basis of our reactive evaporation system, we conducted a detailed study of GaN epitaxy on silicon substrate, doping and UV photodetector and achieved some encouraging results. 1. For the first time, we reported wurtzite single crystalline GaN grown on Si (111) substrates using a CaN polycrystalline buffer layer by a very simple reactive evaporation technique. The growth technique described was simple but very powerful for growing single crystalline GaN films on Si substrates. -5- 2. The scanning electron microscopy (SEM), X-ray diffraction (XRD), Transmission electron microscopy (TEM), Photoluminescence (PL), Hall measurement and Second ion mass spectroscopy (SIMS) were performed to characterize the surface morphologic, structural, optical and electronic properties of the GaN films. The results of characterization indicated that the GaN films grown on the Si( 111) substrate had a good quality 3. Using the special equipment of Si substrate heated from both sides, the step by step cooling processing after growth and the buffer layer technology, We can effectly suppress.the cracking of GaN thin films grown on Si substrate. 4. Adopting the buffer layer technology of gradually changing lattices, we used the Si3N4 as a buffer layer. It was found this layer could potentially affect the bonding structure of the GaN/Si interface and be goog to form GaN polycrystalLine buffer layer, provide a much better template for the subsequent GaN epitaxy on silicon at high temperature. 5. Based on the analysis of the cross-sectional HRTEM image of the OaN/Si interface and the SPIED images in the interfacial area, we presented the orientation relationship and also a growth mechanism of GaN epitaxy on silicon substrates in this system. It was revealed that a phenomenon of self-resembled structure existed in the GaN thin films grown on Si substrate. We thought the growth style of mixed type (S-K type) was fitted for the GaN grown on Si by the reactive evaporation. 6. We successfully achieved a p-n junction structure in GaN epilayer by implantation of...
Keywords/Search Tags:Investigation
PDF Full Text Request
Related items