| This paper is supported by 863 projects(No. 2015AA033305), The main contents are as follows:For its unique material advantages, Ga N material has received extensive attention in the field of power electronics. Its introduction can solve the shortage of silicon materials very well, moreover, the Al Ga N / Ga N heterostructure takes full advantage of Ga N material, it can produce high mobility and a high concentration of twodimensional electron gas in the heterojunction surface, As this basis, Al Ga N / Ga N heterostructure Schottky barrier diode(SBD) is an important part of the Ga N-based power electronic devices. This paper is divided into three parts for Al Ga N / Ga N SBD study and discussion.Before device fabrication, we simulated and optimized the structural parameters of the device by TCAD-ATLAS simulation software. Firstly, the internal mechanism of effect of changes in Al composition to bring the device characteristics was analyzed, and Al component was made a trade-off, Then analyzed the impact of changes on the device characteristics brought by Lac and compared simulation data with the experimental data. Finally got device design principles, At last, the influence of the field-plate's length and thickness of the passivation layer brought to the device breakdown characteristics was analyzed, it found that the introduction of field plate can really optimize the breakdown characteristics, but the increases of the length of the field plate had no significant optimization for breakdown characteristics. Next, we put our focus on the influence of the thickness of the passivation layer, found that both single or dual field plate field plate, and then extended to the multi-field plate, only the passivation layer thickness of uppermost field plate has a decisive effect on the device breakdown characteristics. When the field plate can be uniformly dispersed internal electric field device, Device breakdown voltage can be maximum.The ring structure of the P- type Si substrate Al Ga N / Ga N SBD was fabricated. we studied schottky electrode annealing, found that when annealing conditions were 300?, 30 min, devices reverse leakage performance was best optimizd, then its thermal characteristics were analyzed, barrier height and the ideal factor was extracted by using I-V test method. It found that the barrier height gradually increases with temperature, the change of ideality factor is unstable, remained at around 1.75, showed a downward trend. By fitting Forward I-V curve under different mechanisms, analyzed the reason for ideality factor deviatting from 1. Finally the device reverse leakage current and breakdown voltage with temperature changes was analyzed.Multifinger-patterned SBD was fabricated, size 2000?m × 1860?m device operating current was up 1.7A@3V, much larger than the operating current of the ring structure, analyzed the ohmic electrodes thicker, wire bonding to device performance optimization from current crowding, then compared the current density of the different fingers and ring structure, it was found that electronic concentrated on the edge of the Schottky electrode by ATLAS simulation, Resulting in reducing effective area of the Schottky electrode, but the multifinger-patterned SBD can solve this problem well because of its elongated shape of the electrode. Finally, compared the operating current of the different finger device, further illustrate the negative impact of current crowding effect. |
PDF Full Text Request