Research On Schottky Diode With High Rectification Efficiency For Weak Energy Wireless Harvesting

With the increasing abundance of RF energy in the environment and the popularization of ultra-low power consumption electronic devices,wireless energy harvesting technology has developed into a new environmentally friendly power supply solution that better meets the sustainable development requirements of the times.It has attracted much attention at home and abroad.The RF energy harvesting technology receives a great quantity of RF energy distributed in the environment and converts it into DC energy.However,the main RF energy density in the environment is relatively low,which affects the rectification efficiency of the entire system and cause a waste of energy.Consequently,in order to improve the utilization rate of energy,it has become a development trend to study RF energy harvesting systems with high rectification efficiency under the condition of low input power.In view of this,the ultimate goal of this topic is to improve the rectification efficiency of the RF energy harvesting system under the condition of 2.45G weak energy density.Starting from the structure optimization of Schottky diode(SBD),the core component of the rectifying circuit,establish two physical models of rectification efficiency and turn-on voltage of Schottky diode by theoretical studying,and based on Silvaco simulation,a new Schottky diode device structure with high rectification efficiency suitable for 2.45G weak energy density is proposed.The research work of this paper is as follows:1.Research on the key physical parameter models of SBD under weak energy density:Based on the basic structure of SBD,its rectification mechanism is studied,and the internal relationship between SBD electrical parameters and conversion efficiency under weak energy density is revealed,that is,the reduction of turn-on voltage,series resistance and junction capacitance help to improve the conversion efficiency of SBD under weak energy density;the turn-on voltage decreases with the increase of electron effective mass and affinity energy.By establishing the key physical parameter models of SBD,it aims to provide important theoretical basis and reference for the subsequent design of SBD devices with high rectification efficiency under weak energy density.2.Research on model verification and SBD design:ADS simulation tool is used to verify the key physical parameter models.The simulation results are consistent with the conclusions obtained.Based on this,this paper proposes the optimal design principle of SBD under weak energy density.The first is to reduce the series resistance.The high-mobility material Ge_1-xSn_x alloy is used.The second is to use Si with larger effective mass to reduce the turn-on voltage,and to study the anisotropy of the affinity of each Si crystal plane.The result shows the affinity of(100)crystal plane is the highest.Then proposes a(100)crystal plane Si stacked GeSn SBD.In addition,aimed at the lack of quantitative results of Ge_1-xSn_x alloy carrier mobility,based on the kp perturbation theory and carrier scattering mechanism,establishes the quantitative analysis model of carrier mobility to obtain Ge_1-xSn_x mobility.Compared with Ge,its mobility is nearly doubled.3.Simulation research on Si stacked GeSn SBD under weak energy density:Using the Silvaco simulation tool,adjust the material and structure parameters of SBD,and obtain the forward I-V,C-V and breakdown characteristic curves by electrical simulation.Use Cadence software to extract Spice parameters of the SBD,and use ADS to verify the rectification efficiency,which the Si stacked GeSn SBD designed in this paper is used as the core device of system energy conversion.The results show that the turn-on voltage of Si stacked GeSn SBD is about 0.18V,which is much lower than the traditional SBD;At-10d Bm,the rectification efficiency is improved by 20%compared with the Schottky diode without Si layer,and the efficiency can reach 42.1%after simple LC matching.In summary,the research work on the establishment of the key physical parameter models of SBD and the quantification model of Ge_1-xSn_x material carrier mobility,and the design work of Si stacked GeSn SBD with high rectification efficiency for low energy density in this paper can provide important reference value for the design of core components of rectifying circuit in weak energy wireless energy harvesting system.