Development Of PiN Device Based On 6H-SiC Single Crystal

As the third generation semiconductor material,silicon carbide?SiC?has the advantages of wide bandgap,fast saturated electron drift velocity,high critical breakdown field strength,high thermal conductivity and radiation resistance.Therefore,SiC devices can work under special conditions such as high temperature,high power,high frequency and strong radiation.SiC PiN devices have great advantages in nuclear radiation detectors.Firstly,the excellent material properties of SiC enable the devices to work in high temperature and strong radiation environment.In addition,the thickness of the sensitive region of PiN structure is large,which is suitable for the detection of high-energy radiation.Therefore,the research of SiC PiN devices has become one of the hotspots of semiconductor nuclear radiation detectors.In this paper,6H-SiC PiN devices were fabricated based on ion implantation technology,and their electrical properties are studied.SRIM software was used to simulate the distribution of N and Al ions in SiC under different implantation conditions.The number of implantation times and specific conditions of N and Al ion implantation were simulated.The uniform distribution of N and Al ions in the500 nm SiC implantation area was achieved by multiple implantation combined with the last large angle implantation.Semi-insulating 6H-SiC single crystals were implanted with N and Al ions,respectively.The lattice damage were repaired and electrical activation of implanted ions by annealing for120 minutes at 1450?.Secondary ion mass spectrometry?SIMS?showed that the implanted ions moved to a certain extent after annealing.At the same time,the concentration peaks of N and Al ions decreased due to the diffusion at high temperature annealing.X-ray diffraction spectra show that small twinning peaks appear at 35.54 and 75.32 degree diffraction peaks of6H-SiC implanted with N and Al ions,respectively,and the full width at half maximum?FWHM?of the main peak at 35.54 becomes wider.After high temperature annealing,the twinning peaks disappear and the half-height width becomes wider.Raman spectra show that the half-height of characteristic Raman peaks at 765.85 cm^-1,788.03 cm^-11 and 964.48 cm^-1will be broadened by N and Al ion implantation,and that the 6H-SiC will have new Raman peaks and some old Raman peaks will disappear after annealing.Hall and I-V characteristics of implantation surface show that both N and Al ions are electrically activated to a certain extent after high temperature annealing.Finally,6H-SiC PiN devices were fabricated by implanting N ions on the Si surface and Al ions on the C surface using ion implantation technology.It was found that defects were introduced into SiC by ion implantation,and high temperature annealing recovered to a certain extent.By I-V and C-V characteristic test,the open voltage of 6H-SiC PiN device is3.026V,and the leakage current density of the device is 1.35×10^-4A/cm² at-50V.By testing the ultraviolet response characteristics of the device,it is observed that the reverse photocurrent of 6H-SiC PiN is 2-3 times higher than that of dark current at different reverse bias voltages,and the response of the device is 1.43×10^-3A/W and 6.44×10^-3A/W at 0V and10V reverse bias voltages,respectively.