Hydrogen plasma induced defects in silicon

Abstract

The nature of extended defects in silicon introduced by hydrogen containing plasmas has been studied by transmission electron microscopy for a variety of technological processes. Depending on the doping level of the substrate, the substrate temperature and the presence/absence of simultaneous energetic ion bombardment, {111} planar defects, gas bubbles, and a heavily damaged near-surface region have been observed.

Characterization of {111} planar defects induced in silicon by hydrogen plasma treatments

“…The as-removed Si layer should be single crystalline and, ideally, free of defects for use in multilayer architecture of the 'single crystal layer/amorphous insulating layer/single crystal substrate' type. Ion implantation or treatment in a plasma of light atomic species, such as H or He, is a practical way of inducing crystal defects with a certain distribution profile under the Si wafer surface [5][6][7][8][9][10]. *Corresponding author.…”

Below-band-gap electroluminescence related to doping spikes in boron-implanted siliconpndiodes

“…The peak P B is similar to the photoluminescence peak observed in the hydrogenated lightly boron-doped silicon containing defects clusters and strained {111} planar defects. [18][19][20] Due to the low boron concentration, the band-gap shrinkage arising from the p-type doping can be neglected in the reference sample ͑D*͒, so the peak energy of P B below the band gap is mainly related to strain-induced band-gap shrinkage near the planar {111} defects of silicon interstitial clusters. The origin of P A peak is unclear.…”

Low-temperature in situ cleaning of silicon (100) surface by electron cyclotron resonance hydrogen plasma

“…Jeng et al measured the hydrogen concentration in Si as high as 10 20 /cm 3 by secondary-ion mass spectrometry ͑SIMS͒ after hydrogen-containing plasma exposure, and reported the similar planar defects. 9 If the penetration of hydrogen is purely by thermal diffusion of hydrogen atoms from the gas to the Si, the hydrogen concentration profile and the defect formation will remain unaffected by the substrate dc bias. The fact that the substrate dc bias influences the defect formation strongly supports the idea that the defect formation during hydrogen plasma cleaning is mainly caused by hydrogen ions.…”

“…͕111͖-type planar defects are clearly seen, and it was proposed that they are originated from the condensation of excess hydrogen in Si along ͕111͖ planes. 8,9 Crystalline defect formation in Si substrates during hydrogen plasma cleaning is presumed to be caused by hydrogen penetration into Si. The possible defect generators are hydrogen atoms, or ions, or both.…”

“…6,7 However, the defect formation in Si wafer is reported when the wafer is exposed to hydrogen-containing plasmas at low temperatures in a non-UHV system. 8,9 A remote hydrogen plasma cleaning is devised to remove the native oxide without plasma damage, but even in remote plasma configuration defect formation was reported at some conditions, possibly by ion impingement. 7 We previously reported that a 2 min electron cyclotron resonance ͑ECR͒ hydrogen plasma cleaning at 560°C is severe enough to generate crystalline defects in Si substrates, and it was possible to suppress the defect formation by applying ϩ10 V to the substrate during in situ cleaning.…”