Gallium nitride high electron mobility transistor having inner field-plate for high power applications

Abstract

A gallium nitride high electron mobility transistor, in which an inner field-plate is disposed between the gate and drain of the high electron mobility transistor, so that an electric field is distributed between gate and drain regions to reduce a peak value and to reduce gate leakage current while maintaining high frequency performance, thus obtaining a high breakdown voltage, reducing the capacitance between the gate and the drain attributable to a shielding effect, and improving linearity and high power and high frequency characteristics through variation in the input voltage of the inner field-plate. The gallium-nitride high electron mobility transistor includes a gallium nitride buffer layer. An aluminum gallium-nitride barrier layer is formed on the buffer layer. A source electrode is placed on the barrier layer. A drain electrode is placed on the barrier layer to be spaced apart from the source electrode. A gate electrode is placed on a top of the barrier layer to be spaced apart from the source electrode and the drain electrode. A dielectric layer is deposited on the top of the barrier layer. An electric field electrode is formed on the dielectric layer located on the gate electrode. An inner field-plate is formed in the dielectric layer to be spaced apart from the gate electrode and the drain electrode.

1 . A gallium-nitride high electron mobility transistor, comprising:
 a gallium nitride (GaN) buffer-layer;   an aluminum gallium-nitride (GaAlN) barrier layer formed on the buffer layer;   a source electrode placed on the barrier layer;   a drain electrode placed on the barrier layer to be spaced apart from the source electrode;   a gate electrode placed on a top of the barrier layer to be spaced apart from the source electrode and the drain electrode;   a dielectric layer deposited on the top of the barrier layer;   an electric field electrode formed on the dielectric layer located on the gate electrode; and   at least one inner field-plate formed in the dielectric layer between the gate electrode and the drain electrode to be spaced apart from the gate electrode and the drain electrode.   
   
   
       2 . The high electron mobility transistor according to  claim 1 , wherein the inner field electrode is formed to overlap the electric field electrode in a stacked structure. 
   
   
       3 . The high electron mobility transistor according to  claim 1 , wherein the inner field-plate is formed so that it does not overlap the electric field electrode, or so that boundaries of the inner field-plate and the electric field electrode are aligned with each other. 
   
   
       4 . The high electron mobility transistor according to  claim 1 , wherein a voltage to be applied to the inner field-plate is a voltage between voltages applied to the gate electrode and the drain electrode. 
   
   
       5 . The high electron mobility transistor according to  claim 4 , wherein a voltage to be applied to the electric field electrode is a voltage applied to the source electrode, the gate electrode, or the drain electrode. 
   
   
       6 . The high electron mobility transistor according to  claim 1 , wherein the inner field-plate is formed so that a plurality of inner field-plates is formed between the electric field electrode and the drain electrode while overlapping each other in a sequentially stacked structure. 
   
   
       7 . The high electron mobility transistor according to  claim 1 , wherein the inner field-plate is formed so that a plurality of inner field-plates is formed between the electric field electrode and the drain electrode such that the inner field-plates do not overlap each other, or such that boundaries thereof are aligned with each other. 
   
   
       8 . The high electron mobility transistor according to  claim 6  or  7 , wherein voltages to be applied to the plurality of inner field-plates are voltages between voltages applied to the gate electrode and the drain electrode. 
   
   
       9 . The high electron mobility transistor according to  claim 1 , wherein the electric field electrode is connected to either one of the gate electrode and the source electrode through a conductor.