Design of a Schottky Metal-Brim Structure to Optimize 180–220 GHz Broadband Frequency Doubler MMIC

Luwei Qi,Dehai Zhang,Zhi Jin,Jin Meng,Chengyue Yang,Jingtao Zhou,Xiaoyu Liu

doi:10.3390/electronics9050715

Abstract

The present work proposes a 180–225 GHz broadband frequency doubler monolithic microwave integrated circuit (MMIC) based on a novel Schottky barrier diode (SBD) terminal structure denoted as a Schottky metal-brim (SMB). Compared with an MMIC adopting the conventional SBD terminal structure, preliminary measurements show that the maximum output power of the MMIC adopting the SMB structure increases from 0.216 mW at 206 GHz to 0.914 mW at 208 GHz. Analysis of the nonlinear current–voltage and capacitance–voltage characteristics of the two terminal structures based on an extended one-dimensional drift-diffusion model, indicates that the SMB structure provides significantly better conversion efficiency than the conventional SBD structure by eliminating the accumulation of charge and additional current paths near the Schottky electrode edge. It provides a feasible scheme for the optimization of MMIC applications requiring high power and high efficiency.

Highlights

Terahertz science and technology have developed rapidly in recent decades, and this has promoted the use of THz radiation in many high-requirement applications, such as astrophysics and earth science, high-speed communication, biomedicine, and safety imaging [1,2,3]
The proposed Schottky barrier diode (SBD) structure is designed to eliminate the accumulation of charge and additional current paths near the Schottky electrode edge by better isolating the n-type GaAs epitaxial layer, which is beneficial for monolithic microwave integrated circuit (MMIC) applications requiring high power and high efficiency
The output power of both frequency doubler MMICs would be greater with a larger power

Summary

Introduction

Terahertz science and technology have developed rapidly in recent decades, and this has promoted the use of THz radiation in many high-requirement applications, such as astrophysics and earth science, high-speed communication, biomedicine, and safety imaging [1,2,3]. A critical component in THz systems is electronic sources based on a local oscillator (LO) followed by a combination of amplifiers and frequency multipliers with sufficient output power [4,5]. The tremendous interest in THz technology has led to the development of a series of local oscillators operating in the THz band (i.e., 100 GHz to 30 THz) [6]. Frequency multiplier chains based on Schottky diodes have been commonly employed due to their advantages of low cost, frequency agility, easy integration, and good functionality both at room temperature and at cryogenic temperatures [7,8,9]. A number of advanced semiconductor technologies have been developed worldwide for frequency multiplier applications in the THz band.

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