ABSTRACT
Abstract. In this paper, we report a new technique to enhance breakdown voltages and output conductances of AlGaAs/InGaAs/GaAs pHEMTs. This structure used field plate (FP) in the form of composite gate. Composite gate was fabricated using digital recess method. A breakdown voltage of a single gate device was 6.4V and output conductances were 17mS/mm. The proposed structure with composite gate achieved 9.8 V breakdown voltage and 5.5 mS/mm output conductances. 12
1. Introduction Recently, the development of high frequency devices such as GaAs HEMT or GaN HFET is advanced rapidly for high breakdown voltage and high electric current density. Although the GaAs HEMT has superior frequency response to the GaN HFET, the characteristics of electric power of the GaAs HEMT is not so good. Therefore, it is necessary to improve the breakdown voltage. The composite gate that proposed in this paper is the structure that added a second gate to a general single gate GaAs HEMT. Each gate was recessed with digital recess method, which can control the current to the required levels with the frequency of recess. This is another implementation of the field plate structure and has shown the improved breakdown voltage and output conductance.
