Intense ionizing irradiation-induced atomic movement toward recrystallization in 4H-SiC

Abstract

An ultrafast thermal spike within a time interval of a few pico-seconds generated by intense ionizing energy deposited using 100 MeV Ag ions is utilized to study the atomistic details of damage recovery in 4H-SiC. Sequential single ion irradiations were performed using 300 keV Ar and 100 MeV Ag in ⟨0001⟩ 4H-SiC to invoke swift heavy ion (SHI) beam induced epitaxial recrystallization in samples with different degrees of pre-damaged conditions. SHI irradiation was carried out at both room temperature and a low temperature of ∼80K. Low-temperature irradiation was carried out to arrest thermal diffusion of defects and to isolate ionization-induced defect migration in 4H-SiC. Insights into the thermal spike generated by ionizing events in crystalline and amorphous regions at both the temperatures predict a SiC response to SHI. The results emphasize the role of different degrees of pre-damage induced physico-chemical conditions and irradiation temperatures against SHI-induced recrystallization as evaluated by Rutherford backscattering/channeling, Raman spectroscopy, and hard x-ray photoelectron spectroscopy. Understanding the dependence of ion-beam damage accumulation and their recovery on the inelastic to elastic energy loss ratio is important for the performance prediction of SiC intended for extreme environments such as space, defense, and nuclear radiation. We report substantial damage recovery even at a near liquid nitrogen temperature of ∼80K. The recovery gets impeded mainly by the formation of complex defects having homonuclear bonds. The results are explained in the framework of the inelastic thermal spike model, and the role of phonon in the damage recovery process is emphasized.

Monitoring of the recovery of ion-damaged 4H-SiC with in situ synchrotron X-ray diffraction as a tool for strain-engineering

“…The extent of recovery is found to depend on the amount of surrounding crystalline regions around the amorphous/disordered regions, as evident from the higher recovery observed at the boundaries of the crystalline-amorphous region as compared to the centre. This is consistent with previous studies where it has been concluded that epitaxial recrystallization requires a sufficient amount of crystalline surroundings that acts as the deciding factor for the extent of observed damage recovery [10,11,29,30]. Annealing at 1273 K for 30 min recovers significant damage, however, the RBS/C yield remains much greater than that of the pristine.…”

“…Recently, it has been demonstrated that strain relaxation occurs from ionization-induced annealing of 21 MeV Ni ion in predamaged 4H-SiC [9]. Also, we recently verified that the rapid thermal-spike caused by the strong ionizing energy deposited by 100 MeV Ag ions results in structural and chemical damage recovery in 4H-SiC [10]. Besides, the role of swift heavy ion irradiation in the generation of controlled defects has also been studied [11].…”

“…Before and after thermal annealing, the calculated disorder values from Raman data are 0.39 and 0.18, respectively. The disorder from Raman is estimated as 1-A, where A is the sum of the area under the first-order Raman modes in the irradiated material normalized with respect to that of the pristine crystal [10,11,17]. The percentage of recovery calculated in this case is 52.1%.…”

“…Annealing at 1273 K for 30 min recovers significant damage, however, the RBS/C yield remains much greater than that of the pristine. To quantitatively assess damage annealing, recovery percentage [10,11] is estimated to be 54.4%. The recovery percentage is evaluated using the data shown in Figure 1(b).…”

Back‐End‐of‐Line SiC‐Based Memristor for Resistive Memory and Artificial Synapse

“…The former can be attributed to the metallic Si 0 (Si–Si bonding) while the latter is the characteristic peak for Si–C bonding. [ 33,34 ] The C 1s spectrum is characterized by a single peak at 283.0 eV. This suggests our CVD grown SiC layer is a mixture of Si and SiC which leads to the unique switching performance of the memristor.…”