Drain Corrosion in RF Power GaAs PHEMTs

Abstract

Si02Suc ri We have investigated drain degradation in a set of passivation Source G Drain experimental RF power GaAs PHEMTs. Drain degradation ohmics_ was observed in the form of an increase in RD and aca reduction in Imax in a variety of conditions. We found that tcGhstA both forms of degradation arise from surface corrosion that AIGaAs takes place on different locations on the drain and chantne dominate in different regimes of operation. Specifically, AIGaAs the increase in RD was prominent in the ON-state and was Gua found to be associated with corrosion on the drain n+GaAs ledge. The reduction in Imax, in contrast, was prominent in Figure 1: Schematic cross-section of GaAs PHEMT under study. Lg the OFF-state and was associated with corrosion on the 0.25 um,r BVDG,off=l2-l5 V, fT 40-50 GHz.

Degradation Uniformity of RF-Power GaAs PHEMTs Under Electrical Stress

“…A consequence of this is to produce a change in the pattern of degradation, as the experiment advances with the edges lighting up as the stress voltage is increased. Separately, in these devices, we have found that the main electricaldegradation mechanism under the conditions studied in this paper is corrosion of the n+ GaAs cap on the drain side of the device [6], [7]. We also found that this mechanism is strongly driven by electric field and temperature.…”

“…The reduction in light emission for constant V DS in the late stages of the experiment indicates a reduction in impact ionization that is probably due to R D degradation decreasing the intrinsic V DG that is applied to the device [12]. R D degradation is a consequence of the aggressive electrical stress applied to this device [6], [7], [14]. 2 shows light-emission images obtained at various times during the experiment.…”

“…Several degradation mechanisms have been identified that are driven by electric field [1], [4], [7]. Nonuniform electric-field distributions will preferentially degrade certain areas of a device at the risk of producing premature device failure.…”

“…Since these devices typically operate at high power levels and under high-voltage biasing, their electrical reliability is of serious concern. Previous studies in these devices have identified several distinct degradation phenomena that have different accelerating factors [1]- [7]. To date, reliability studies generally assume that degradation takes place uniformly across the width of the device.…”

Simultaneous achievement of high performance and high reliability in a 38/77GHz InGaAs/AlGaAs PHEMT MMIC

“…We have previously reported a comprehensive study of degradation of AlGaAs/InGaAs PHEMTs during operation under high humidity conditions [3,4]. We have concluded that PHEMT degradation is caused by an electrochemical corrosion reaction between the semiconductor and H 2 O that takes place at the SiN x /semiconductor interface on the drain side of the device.…”