Atomic rearrangement of amorphous silicon by Sub-1 keV electron irradiation in plasma

Abstract

To realize the potential of ion implantation in the production of semiconductor devices, thermal annealing have been developed to remove the implant damage and to electrically activate the dopants. With the trend in the silicon industry toward further miniaturization, with 3D structure for higher integrity, and monolithic 3D integration, there is a growing demand to remove the damage produced by ion implantation with low thermal budget. Ion and electron-beam-induced recrystallization have been studied for low temperature crystallization since bombardment of ion and electron can reduce the activation energy of crystallization by bond breaking or interstitial defect generating. Herein, crystallization method having large scalability called ‘Plasma electron-induced crystallization (PEIC)” is proposed, while PEIC remove the damage with the aid of bombardment with energetic electrons. To prove whether PEIC has strength in crystallization from energetic electron bombardment, fundamental experiments comparing with rapid thermal annealing (RTA) are conducted with TEM, XRD, SIMS sheet resistance and Raman analysis. Electron bombardment to the sample in the plasma, reduce the activation energy of crystallization, which means PEIC has small thermal budget compared to RTA. Deep study on the mechanism of PEIC coming from its uniqueness which is very low electron energy with bombardment and joule heating simultaneously, is conducted. To claim mechanism of PEIC is bond relaxing, recrystallization rate is investigated according to different temperature of PEIC and RTA. Deposited amorphous silicon is also crystallized by PEIC with relatively low temperature since Si atoms are easy to be locally ordered with the aid of bond relaxing. To apply the PEIC to the future Si device structure and 3d monolithic integration, the evaluation of PEIC potential in future low thermal budget annealing process is conducted with bulk Si wafer, Ring gate MOSFET, conventional planar MOSFET.