Papers by Keyword: Surface Recombination Velocity

Abstract: We have proposed an E-V-C (Expansion-Visualization-Contraction) method by using UV irradiation, for screening potential defects which causes reliability issue called bipolar degradation in 4H-SiC devices. This method is based on the property that the REDG (recombination-enhanced dislocation glide) mechanism causing the bipolar degradation can be reproduced by UV irradiation. However, in order to apply this method as a screening, accurate quantification of the correlation between current density in forward bias and UV irradiance is required. This article describes how to set UV irradiation conditions (irradiance and irradiation time) to simulate forward biased current conditions.

Abstract: Surface electronic quality of wet-cleaned Si wafers was characterized quantitatively and all-optically via spatially-resolved surface recombination velocity (SRV) imaging using InGaAs-camera-based dynamic heterodyne lock-in carrierography. Six samples undergone four different hydrofluoric special-solution etching conditions were tested, their SRV distributions at different queue times after the hydrogen passivation processes were obtained, and a quantitative assessment of their surface electronic quality was made based on the evolution behavior of globally-integrated information from the SRV images. The data acquisition time for an SRV image with full camera pixel resolution was about 3 min. The methodology introduced here is promising for in-line nondestructive testing/evaluation and quality control at different fabrication/manufacturing stages in the electronic industry. Keywords: heterodyne lock-in carrierography, surface recombination velocity, quantitative imaging, HF etching, Si wafers

Abstract: We evaluated the carrier lifetime to estimate surface recombination velocities for 4H-SiC whose surfaces were treated by various processes. We found that the reactive ion etching (RIE) increased the surface recombination velocity, and we considered that point defects introduced by RIE influence the surface recombination velocity.

Abstract: We evaluate the performance capabilities and limitations of high voltage 4H-SiC based Bipolar Junction Transistors (BJTs). Experimental forward characteristics of a 4kV BJT are studied and simulations are employed to determine the factors behind the higher than expected specific onresistance (Ron,sp) for the device. The impact of material (minority carrier lifetimes), processing (surface recombination velocity) and design (p contact spacing from the emitter mesa) parameters on the forward active performance of this device are discussed and ways to lower Ron,sp, below the unipolar level, and increase the gain (β) are examined.