Excess Carrier Lifetime in a Bulk p-Type 4H–SiC Wafer Measured by the Microwave Photoconductivity Decay Method

Abstract

The asymptotic spherical aberration and distortion coefficients of electron lenses always depend upon the position of the object, or the magnification, in a very simple way, and furthermore the quantities that specify the distortion are closely related to those giving the spherical aberration. These relationships are set out, and numerical values of the coefficients concerned are tabulated for Glaser's bell-shaped model; both the symmetric and the asymmetric bell are considered, and the effect of scaling with respect to the minimum projector focal length is investigated.

Enhancement and control of carrier lifetimes in p-type 4H-SiC epilayers

“…Danno et al succeeded in achieving lifetime control for an n-type 4H-SiC epilayer by changing the Z 1/2 concentration using electron irradiation. 6 However, these beneficial results have mainly addressed the n-type 4H-SiC, with very few reports on the carrier lifetimes in thick and lightly doped p-type SiC, 14,15 which is often employed as the voltage-blocking region of high-voltage SiC switching devices such as thyristors 16 and insulated gate bipolar transistors (IGBTs). 17 In this work, the authors attempted to enhance carrier lifetimes in p-type 4H-SiC by employing thermal oxidation or carbon implantation, each of which is effective for lifetime enhancement in n-type SiC.…”

Suppression of stacking fault expansion in a 4H-SiC epitaxial layer by proton irradiation

“…During UV illumination, the specimens were heated to 373 K to expand the stacking fault by reference to the previous study 46 , and the temperature was measured by a radiation thermometer. The carrier lifetime of the specimens was evaluated by time-resolved photoluminescence (TR-PL) using a bandpass filter with a transmission wavelength of 370–410 nm, corresponding to luminescence from the band edge of 4H-SiC (~ 390 nm), as well as microwave photoconductivity decay (μ-PCD) with 10 GHz microwaves as a probe 12 , 50 . The excitation source for TR-PL and μ-PCD was a 266 nm pulsed laser with an injected photon density of 1 × 10 14 cm −2 .…”

Excess carrier lifetime and strain distributions in a 3C-SiC wafer grown on an undulant Si substrate

“…On the basis of excess carrier decay curves obtained from μ‐PCD, we mapped the 1/ e lifetime, which is defined as the time taken by the excess carrier to decay from a peak to 1/ e . The portions with strain field could be observed by a microscope with crossed polarizers, which is frequently used to observe defect distribution in SiC wafers . Although we did not have the microscope with a setup to observe amount of strain and stress as reported in Refs.…”

“…Therefore, distribution in the density of defects may show correspondence with carrier‐lifetime distribution. As reported for other SiC polytypes, carrier‐lifetime measurements are effective for observing non‐uniform electrical properties caused by defects in a SiC wafer . Recently, we studied the carrier‐lifetime distributions in (100) surfaces of a 3C‐SiC wafer using microwave photoconductivity decay (μ‐PCD) with sub‐mm mapping .…”