Proton Irradiation of High Aluminum Content AlGaN Polarization Doped Field Effect Transistors

Abstract

The effects of proton irradiation dose on the DC and switching properties of high aluminum content, polarization-doped field effect transistors (POLFETs) were studied. The POLFETs were irradiated at proton energy of 10 MeV at fluences of 1 × 1014 cm−2 and 3 × 1014 cm−2. The DC saturation current exhibited a 21 and 36% reduction at fluences of 1 × 1014 cm−2 and 3 × 1014 cm−2, respectively. The carrier removal rates for this energy was 677 cm−1. However, switching current at 100 kHz demonstrated no change, with near ideal performance, as opposed to significant degradation in their GaN HEMT counterparts. This near ideal performance is attributed to the volume of the 3D electron gas in the POLFETs reducing the likelihood of negatively impacting scattering events, as opposed to the narrow 2D electron gas of the HEMT. The DC degradation and carrier removal rates are on par with reported traditional GaN HEMTs, but the switching performance is exceptionally improved.

Alpha Particle Irradiation of High Aluminum Content AlGan Polarization Doped Field Effect Transistors

“…As such, using an order of magnitude lower fluence with alpha radiation should produce similar degradation as observed in the proton irradiation when dose is accounted for. While the energy in 9 is not identical to the energy used for alpha particles in this work, the shift in stopping power for 10 MeV vs 18 MeV in Fig. 1 for protons is small.…”

“…It is interesting to contrast the results described here for alpha particle irradiation with our previous studies of the effects of proton irradiation on these same device structures. 9 The proton irradiation in that case was performed at fluences of 1 × 10 14 cm −2 and 3 × 10 14 cm −2 at 10 MeV. From Eqs.…”

“…Alpha particle radiation due to its heavier mass presents a larger risk to both electronics and life forms in space than proton irradiation. [5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20] Alpha particle events in GaN High Electron Mobility Transistors (HEMTs) have been studied previously, although not nearly as well as proton irradiation. Danesin et al reported on 2 MeV alpha irradiation and noted a 70% reduction on drain current at a fluence of 10 14 cm −2 .…”

“…Figure5. Comparison of carrier removal rates for radiation damaged POLFETs and previously reported GaN HEMT based lateral devices as a function of radiation energy and type [5][6][7][8][9][10]22. …”

Review—Radiation Damage in Wide and Ultra-Wide Bandgap Semiconductors

“…Damage processes in semiconductors.-In addition to growthrelated defects, radiation-induced defects in materials are produced through electronic (ionizing and charge transfer) effects and nuclear displacement damage. 166,[176][177][178][179][180][181][182][183][184][185][186][187][188][189][190][191][192][193][194] There may also be damage to insulators used to apply voltage to the gate of a transistor structure. Inelastic linear energy transfer (LET) to the electronic structure (also known as electronic stopping power) from high energy particles, as well as from photons (X-rays and lasers), results in the creation of energetic electrons (i.e., ionization and excitation) that initially dissipate their energy in a cascade of electron-electron energy transfers (superheating) that result in the production of electronhole (e)-(h) pairs (the time scale is <fs); [34][35][36][37][38][39] (2) the transfer of much of this energy via electron-phonon coupling to the atomic structure creating a local thermal spike (the time scale is <300 fs); and (3) the formation of localized electronic excitations that can rupture or change the nature of covalent/ionic bonds, enhance defect and atomic mobilities and increase system energy.…”