Record combination fmax · Vbr of 25 THz·V in AlGaN/GaN HEMT with plasma treatment

Min-Han Mi,Ling Yang,Bin Hou,Xiao-Hua Ma,Yang Lu,Heng-Shuang Zhang,Sheng Wu,Meng Zhang,Yue Hao

doi:10.1063/1.5090528

Abstract

A combination of high maximum oscillation frequency (fmax) and breakdown voltage (Vbr) was achieved in AlGaN/GaN high electron mobility transistors (HEMTs) with N2O plasma treatment on the access region. The breakdown voltage is improved from 37 V to 80 V due to the formation of oxide layer in the gate region. A suppressed current collapse is obtained due to plasma treatment on the gate-source and the gate-drain regions. The effect of the present passivation method is almost the same with that of the conventional SiN passivation method, meanwhile it can avoid introducing additional parasitic capacitance due to thinner thickness. The small signal measurement shows that HEMT can yield fT and fmax of 98 and 322 GHz, respectively, higher than that of 70 and 224 GHz for the non-treated HEMT. By using the plasma treatment technique, the HEMT can simultaneously exhibit high fmax and Vbr with a record fmax⋅Vbr of 25 THz⋅V.

Highlights

N surface so as to improve the breakdown voltage and suppress RF gm collapse
N2O plasma treatment has been reported in the previous work, the purpose is different from which is used to improve power added efficiency[11] or to realize normally-off operation.[12]
The N2O plasma treatment in a PECVD chamber can be used to suppress current collapse and RF gm collapse, and avoid extra parasitic capacitance introduced by the conventional passivation scheme

Summary

Introduction

N surface so as to improve the breakdown voltage and suppress RF gm collapse. And that of on gate-source and gate-drain regions is to suppress current collapse. A combination of high maximum oscillation frequency (fmax) and breakdown voltage (Vbr) was achieved in AlGaN/GaN high electron mobility transistors (HEMTs) with N2O plasma treatment on the access region.

Results

Conclusion