Germanium content dependence of radiation damage in strained Si/sub 1-x/Ge/sub x/ epitaxial devices

Abstract

The irradlation damage in n+-Si/p+-Sil-xGex epitaxial diodes and n+-Si/p+-Si l-xGex/n-Si epitaxial heterojunction bipolar transistors (HBTs) by fast neutrons and MeV electrons is studied as a function of fluence and germanium content for the first time. The degradation of the electrical performance of both diodes and HBTs by irradlation increases with increasing fluence, whle it decreases with increasing germanium content. The damage coefficient of reverse current for x = 0.12 and 0.16 dlodes irradated by neutrons is calculated to be 6.2 x and 5.5 x n-lAcm2, respectively. That of h m for electron-irradated x = 0.08, 0.12 and 0.16 HBTs is 7.6 x and 1.6 x 1O-l6e-lcm2, respectively. x

Germanium doping for improved silicon substrates and devices

“…Higher concentrations of germanium (x > 0.15) lead however to significant radiation hardening of devices as was observed in strained Si 1−x Ge x epitaxial devices for electron and neutron irradiation [40,41] and for proton irradiation [42].…”

Impact of mechanical strain on the charge collection mechanisms of nanometer scaled SOI devices under heavy ion and pulsed laser irradiation

“…As an example, mechanical strain will reduce the distance and angles distribution in the silicon, potentially decreasing the formation energies of point defects under ionizing or nonionizing radiations. Then, several papers investigated the impact of strain on the Total Ionizing Dose (TID) response [8,9], the neutron-induced degradation [10] or the heavy ion induced microdose effects [11] in sSi-based devices. On the contrary, only few studies focused on Single-Event Effects (SEE) in strained-silicon devices.…”

Structure and Spatial Distribution of Ge Nanocrystals Subjected to Fast Neutron Irradiation

“…Clash with fast neutrons causes displacement of atoms in the lattice in cascades, which produce a range of sub-nanometer clusters (defect complexes) and radiation damage [19]. These directly contribute to the destruction of the optical and electrical performance of bulk Si and Ge-based devices (such as diodes and hetero-junction bipolar transistors (HBTs) [20]). MOS (Metal Oxide Semiconductor) devices are known to withstand displacement-caused degradation only up to integral dose of 10 15 neutrons/cm 2 [21].…”