Study On The Direct Bonding Of ZnO/GaN

Semiconductor bonding technology can be different characteristics of the lattice mismatch between the contact surfaces of materials through molecular forces or chemical bonding force are bonded together to form a special function structure. The technique involves the theory and practice of mechanical, electrical, chemical, optical, is one of the basic and core technology Preparation of photovoltaic device and MEMS devices. The wide bandgap n-Zn O and p-GaN wide bandgap bonded, can form a very suitable LED light extraction window bonding structure. The topic this objective, will focus on the n-ZnO/p-Ga N direct bonding technology and the ohmic contact involved in the preparation and process for physical problems. The results can be generalized to the preparation of a wide gap other GaN-based and ZnO-based devices with hard materials go, this is a wide-bandgap materials optoelectronic devices and MEMS production of basic work on other hard material bonded important reference.This research can be applied to the LED light extraction window layer of ZnO/GaN bonding structure for the target, and the preparation of directly bonding n-ZnO ohmic contact electrode ZnO/GaN around studies were carried out to obtain the ZnO/GaN n-ZnO ohmic contact electrode directly bonded to the success of the samples and low resistivity, for the realization of a GaN-based LED light extraction window lay a good foundation with ZnO. The main contents of this paper include the following:Firstly, the theoretical analysis and numerical simulation. Theoretically main factors affecting direct wafer bonding were studied, including the ups and downs of the wafer micro-scale, state hydrophilic or hydrophobic surface state of the wafer, the wafer between the particle and the introduction of high-temperature annealing process, determining that the Zn O/GaN wafer direct bonding experiment process parameters required to optimize ZnO/GaN wafer direct bonding process provides a reference.Secondly, was direct bonding process. According ZnO/GaN wafer direct bonding characteristics and process conditions require, developed and designed two fixtures; observe ZnO and GaN wafer surface morphology by optical microscopy and scanning electron microscopy(SEM); thermal stress using Ansys simple simulation analysis; many experiments developed by Zn O/GaN direct wafer bonding process for the realization of a GaN-based LED with ZnO window layer laid a critical foundation technology. The results of several experiments, using optical microscopy and scanning electron microscopy(SEM) from the micro structure, chemical and optical aspects of the ZnO/GaN wafer bonding interface were tested. Research on the ZnO/GaN wafer direct bonding results, suggesting that the experimental process problems, and the results do SEM analysis of Zn O and GaN bonding problems to do a detailed analysis.Finally, the technology of n-ZnO ohmic contact electrode. At different temperatures and other conditions, characterized ohmic contact electrode was prepared with the traditional Ag/Au ohmic contact electrode, and the IV characteristics were studied under different temperature conditions and the ohmic contact resistance, the use of Auger electron spectroscopy(AES), etc. the method of analyzing the structure of an ohmic contact Ag/Au and n-ZnO films formed; comparing and analyzing the structure of the formed ohmic contact and Ag / Au and n-ZnO films conventional metallic electrode and the n-ZnO films formed the optical reflection characteristics of an ohmic contact.