Theoretical Analysis of HEMT Breakdown Dependence on Device Design Parameters Article

Chau, HF, Pavlidis, D, Tomizawa, K. (1991). Theoretical Analysis of HEMT Breakdown Dependence on Device Design Parameters . IEEE TRANSACTIONS ON ELECTRON DEVICES, 38(2), 213-221. 10.1109/16.69897

cited authors

  • Chau, HF; Pavlidis, D; Tomizawa, K

authors

abstract

  • A two-dimensional numerical analysis is nresented to investigate the breakdown characteristics of single- and double-channel AlGaAs/GaAs HEMT’s. The influence of the doped layer thickness as well as the thickness of an undoped i-layer under the gate is analyzed. Impact ionization is considered to be the dominant breakdown mechanism. All simulations revealed the existence of a high electric field region near the gate contact. Breakdown occurs in the gate-drain region and the (breakdown) path which maximizes the ionization integral is entirely in the AlGaAs layer. For increased donor layer thickness, single-channel devices biased near pinchoff have gate-drain breakdown voltages varying from 8 to 14 V with corresponding peak electric field values in the range of 8.2 x 105 to 2.4 x 106V/cm. The breakdown voltage increases with increasing gate bias |Vgs| due to a screening effect of transverse from longitudinal electric field. Double-channel HEMT’s have slightly higher breakdown than single-channel especially near pinchoff and for thin donor layers. The use of large A1 composition, i.e., material of small impact ionization coefficients improves breakdown. Surface depletion does not modify the breakdown considerably (ΔVdg.br~ 0.6 V). © 1991 IEEE

publication date

  • January 1, 1991

published in

Digital Object Identifier (DOI)

start page

  • 213

end page

  • 221

volume

  • 38

issue

  • 2