Ge Schottky diode for improving energy conversion efficiency of the receiver of microwave wireless power transfer

Abstract

Microwave wireless power transfer(MWPT) can break through the restriction of transmission line to transmit electrical energy, which is conducive to dealing with power supply in complex scenarios, and has a very large application prospect. Energy conversion efficiency is an important parameter of MWPT. Hence, researchers are focus on improving the conversion efficiency of MWPT from different ways. Schottky diode is the core component of the rectifier circuit, which determines the limit of the energy conversion efficiency. However, the research involving the design of Schottky diode has rarely reported. In this paper, a GeOI folded space charge region Schottky diode is proposed. The space charge region of the proposed Schottky diode is composed of two parts: the vertical space charge region and the horizontal space charge region. So the capacitor is also divided into two parts, namely the vertical capacitor and the lateral capacitor. In the device model, these two capacitors are in series. So the total capacitance will be reduced. This article establishes its capacitance model and completes the optimization of device material parameters and structure parameters. The designed device parameters are as follows: the doping concentration of the heavily doped buffer layer on the left side of the Ge material is 2 × 10²⁰ cm^–3 to form Ohm contact, the doping concentration of the lightly doped region on the right side is 3.8 × 10¹⁷ cm^–3, the thickness of the folded region is 0.2 μm, the Schottky metal is Wu, the width of metal is 8 μm, and the length of metal is 2 μm. We use the proposed Schottky diode as the core rectifier to simulate the rectifier circuit by using ADS, in which the SPICE parameters of the proposed Schottky diode was extract using Cadence Model Editor. When the input energy is 24.5 dBm, the energy conversion efficiency reached 75.4%. Compared with the conventional schottky diode, the energy conversion efficiency is significantly improved. The study of the proposed Schottky diodes can provide valuable reference for improving the energy conversion efficiency of microwave wireless energy transmission.