High frequency doubling efficiency THz GaAs Schottky barrier diode based on inverted trapezoidal epitaxial cross-section structure

Abstract

A high-performance terahertz Schottky Barrier Diode (SBD) with an inverted trapezoidal epitaxial cross-section structure featuring high varactor characteristics and reverse breakdown characteristics is reported in this paper. Inductively coupled plasma dry etching and dissolution wet etching are used to define the profile of the epitaxial layer, by which the voltage-dependent variation trend of the thickness of the metal-semiconductor contact depletion layer is modified. The simulation of the inverted trapezoidal epitaxial cross-section SBD is also proposed, to explain the physical mechanism of electric field and space charge region area. Compared with the normal structure, the grading coefficient M increased from 0.47 to 0.52, and the capacitance modulation ratio (C max/C min) increased from 6.70 to 7.61. Inverted trapezoidal epitaxial cross-section structure is a promising approach to improve the Variable-capacity ratio by eliminating the accumulation of charge at the Schottky electrode edge. A 190 GHz frequency doubler based on inverted trapezoidal epitaxial cross-section SBD also shows a doubling efficiency of 35% compared to a normal SBD of 30%.