Deep Levels in As-Grown and Electron-Irradiated P-type 4H-SiC

2006 ◽  
Vol 911 ◽  
Author(s):  
Katsunori Danno ◽  
Tsunenobu Kimoto
Keyword(s):  
Cross Section ◽  
Deep Level Transient Spectroscopy ◽  
Capture Cross Section ◽  
Arrhenius Plot ◽  
Deep Level ◽  
Deep Levels ◽  
Emission Time ◽  
Transient Spectroscopy ◽  
P Type ◽  
Thermal Stability Of

AbstractDeep levels in as-grown and electron-irradiated p-type 4H-SiC have been investigated by deep level transient spectroscopy (DLTS). Three hole traps, namely HK2, HK3, and HK4, could be detected in the temperature range from 350K to 700K. Activation energies of the hole traps were estimated to be 0.84 eV for HK2, 1.27 eV for HK3, and 1.44 eV for HK4 from the Arrhenius plot of emission-time constants assuming temperature-independent capture cross section. By double-correlated DLTS (DDLTS), they were revealed to be donor-like (+/0) traps. The concentrations of HK3 and HK4 centers were clearly increased by low-energy (116 keV) electron irradiation. Based on thermal stability of the HK3 and HK4 centers up to 1350°C and the dependence of HK4 concentration on the electron fluence, they may originate from a complex including defect(s) caused by carbon displacement.

Reactive-Ion-Etching Induced Deep Levels Observed in n-Type and p-Type 4H-SiC

2010 ◽  
Vol 645-648 ◽  
pp. 759-762
Author(s):  
Koutarou Kawahara ◽  
Giovanni Alfieri ◽  
Michael Krieger ◽  
Tsunenobu Kimoto
Keyword(s):  
Deep Level Transient Spectroscopy ◽  
Deep Level ◽  
Reactive Ion Etching ◽  
Deep Levels ◽  
Total Density ◽  
Ion Etching ◽  
Initial Concentration ◽  
Grown Sample ◽  
Transient Spectroscopy ◽  
P Type

In this study, deep levels are investigated, which are introduced by reactive ion etching (RIE) of n-type/p-type 4H-SiC. The capacitance of as-etched p-type SiC is remarkably small due to compensation or deactivation of acceptors. These acceptors can be recovered to the initial concentration of the as-grown sample after annealing at 1000oC. However, various kinds of defects remain at a total density of ~5× 1014 cm-3 in a surface-near region from 0.3 μm to 1.0 μm even after annealing at 1000oC. The following defects are detected by Deep Level Transient Spectroscopy (DLTS): IN2 (EC – 0.35 eV), EN (EC – 1.6 eV), IP1 (EV + 0.35 eV), IP2 (HS1: EV + 0.39 eV), IP4 (HK0: EV + 0.72 eV), IP5 (EV + 0.75 eV), IP7 (EV + 1.3 eV), and EP (EV + 1.4 eV). These defects generated by RIE can be significantly reduced by thermal oxidation and subsequent annealing at 1400oC.

Effect of Sacrificial AlN (Aluminum Nitride) Layer on the Deep Surface States of 4H-SiC

2021 ◽  
Vol 21 (3) ◽  
pp. 1904-1908
Author(s):  
Woo-Young Son ◽  
Jeong Hyun Moon ◽  
Wook Bahng ◽  
Sang-Mo Koo
Keyword(s):  
Cross Section ◽  
Deep Level Transient Spectroscopy ◽  
Capture Cross Section ◽  
Deep Level ◽  
Surface States ◽  
Nitride Layer ◽  
Double Negative ◽  
Capture Cross ◽  
Trap Energy ◽  
Transient Spectroscopy

We investigated the effect of a sacrificial AlN layer on the deep energy level states of 4H-SiC surface. The samples with and without AlN layer have been annealed at 1300 °C for 30 minutes duration using a tube furnace. After annealing the samples, the changes of the carbon vacancy (VC) related Z1/2 defect characteristics were analyzed by deep level transient spectroscopy. The trap energy associated with double negative acceptor (VC(2-/0)) appears at ˜0.7 eV and was reduced from ˜0.687 to ˜0.582 eV in the sacrificial AlN layer samples. In addition, the capture cross section was significantly improved from ˜2.1×10-14 to ˜3.8×10−16 cm−2 and the trap concentration was reduced by approximately 40 times.

DLTS Study on Al+ Ion Implanted and 1950°C Annealed p-i-n 4H-SiC Vertical Diodes

2017 ◽  
Vol 897 ◽  
pp. 279-282 ◽  
Author(s):  
Hussein M. Ayedh ◽  
Maurizio Puzzanghera ◽  
Bengt Gunnar Svensson ◽  
Roberta Nipoti
Keyword(s):  
Cross Section ◽  
Deep Level Transient Spectroscopy ◽  
Capture Cross Section ◽  
Deep Level ◽  
Electron Trap ◽  
Double Negative ◽  
Capture Cross ◽  
Carrier Traps ◽  
Transient Spectroscopy ◽  
Post Implantation

A vertical 4H-SiC p-i-n diode with 2×1020cm-3 Al+ implanted emitter and 1950°C/5min post implantation annealing has been characterized by deep level transient spectroscopy (DLTS). Majority (electron) and minority (hole) carrier traps have been found. Electron traps with a homogeneous depth profile, are positioned at 0.16, 0.67 and 1.5 eV below the minimum edge of the conduction band, and have 3×10-15, 1.7×1014, and 1.8×10-14 cm2 capture cross section, respectively. A hole trap decreasing in intensity with decreasing pulse voltage occurs at 0.35 eV above the maximum edge of the valence band with 1×1013 cm2 apparent capture cross section. The highest density is observed for the refractory 0.67 eV electron trap that is due to the double negative acceptor states of the carbon vacancy.

Deep Levels in P-Type 4H-SiC Induced by Low-Energy Electron Irradiation

2013 ◽  
Vol 740-742 ◽  
pp. 373-376 ◽  
Author(s):  
Kazuki Yoshihara ◽  
Masashi Kato ◽  
Masaya Ichimura ◽  
Tomoaki Hatayama ◽  
Takeshi Ohshima
Keyword(s):  
Electron Irradiation ◽  
Deep Level Transient Spectroscopy ◽  
Deep Level ◽  
Deep Levels ◽  
Low Energy ◽  
Epitaxial Layers ◽  
Before And After ◽  
Low Energy Electron ◽  
Transient Spectroscopy ◽  
P Type

We have characterized deep levels in as-grown and electron irradiated p-type 4H-SiC epitaxial layers by the current deep-level transient spectroscopy (I-DLTS) method. A part of the samples were irradiated with electrons in order to introduce defects. As a result, we found that electron irradiation to p-type 4H-SiC created complex defects including carbon vacancy or interstitial. Moreover, we found that observed deep levels are different between before and after annealing, and thus annealing may change structures of defects.

Effect of NO Annealing on 6H- and 4H-SiC MOS Interface States

2010 ◽  
Vol 645-648 ◽  
pp. 499-502 ◽  
Author(s):  
Alberto F. Basile ◽  
John Rozen ◽  
X.D. Chen ◽  
Sarit Dhar ◽  
John R. Williams ◽  
...  
Keyword(s):  
Electrical Properties ◽  
Cross Section ◽  
Deep Level Transient Spectroscopy ◽  
Capture Cross Section ◽  
Deep Level ◽  
Capture Cross ◽  
Temperature Dependent ◽  
Band Energy ◽  
Transient Spectroscopy ◽  
Semiconductor Traps

The electrical properties of the SiC/SiO2 interface resulting from oxidation of the n-type 6H-SiC polytype were studied by hi-lo CV, temperature dependent CV and constant capacitance deep level transient spectroscopy (CCDLTS) techniques. Several trap species differing in energy and capture cross section were identified. A trap distribution at 0.5 eV below the 6H-SiC conduction band energy and a shallower density of states in both the 6H and 4H polytyes are passivated by post-oxidation NO annealing. However, other ultra-shallow and deeper defect distributions remain after nitridation. The latter may originate from semiconductor traps.

Search for Hydrogen Related Defects in p-Type 6H and 4H-SiC

2008 ◽  
Vol 600-603 ◽  
pp. 421-424
Author(s):  
Giovanni Alfieri ◽  
Tsunenobu Kimoto
Keyword(s):  
Thermal Stability ◽  
Deep Level Transient Spectroscopy ◽  
Deep Level ◽  
Electrical Characterization ◽  
Annealing Treatment ◽  
Microscopic Structure ◽  
Electric Field Dependence ◽  
Emission Time ◽  
Transient Spectroscopy ◽  
P Type

Al-doped 4H and 6H epitaxial layers have been implanted with 200 keV hydrogen or irradiated with 1 MeV electrons. Heat treatments have been carried out up to 1000 °C and electrical characterization, by means of deep level transient spectroscopy (DLTS), has been performed after every annealing treatment in the 100-750 K temperature range. We have detected several deep levels and the possible involvement of hydrogen in the microscopic structure of these defects is discussed in the light of their thermal stability and previous results found in the literature. All the detected defects, except for a level located at 0.55 eV above the valence band (Ev), do not display any electric field dependence of their emission time constant.

Shallow and Deep Levels in Al+-Implanted p-Type 4H-SiC Measured by Thermal Admittance Spectroscopy

2015 ◽  
Vol 821-823 ◽  
pp. 403-406 ◽  
Author(s):  
Koutarou Kawahara ◽  
Hiroshi Watanabe ◽  
Naruhisa Miura ◽  
Shuhei Nakata ◽  
Satoshi Yamakawa
Keyword(s):  
Cross Section ◽  
Ionization Energy ◽  
Capture Cross Section ◽  
Deep Levels ◽  
Admittance Spectroscopy ◽  
Capture Cross ◽  
Shallow Acceptor ◽  
Wide Range ◽  
Emission Time ◽  
P Type

Shallow and deep levels in SiC significantly affect dynamic characteristics of SiC devices; larger ionization energy and/or a smaller capture cross-section of levels in the SiC bandgap lead to a larger emission time constant and slower response of carriers. Nevertheless, knowledge about those levels is very limited. In this study, we clarified the ionization energy and the capture cross section of the Al shallow acceptor in 4H-SiC in a wide range of doping concentration by preparing appropriate samples and measuring them by thermal admittance spectroscopy. Furthermore, high densities of deep levels were discovered in Al+-implanted samples, which can degrade 4H-SiC device performance without any care.

Deep Levels Generated by Ion-Implantation in n- and p-Type 4H-SiC

2009 ◽  
Vol 615-617 ◽  
pp. 365-368 ◽  
Author(s):  
Koutarou Kawahara ◽  
Giovanni Alfieri ◽  
Tsunenobu Kimoto
Keyword(s):  
High Temperature ◽  
Deep Level Transient Spectroscopy ◽  
Deep Level ◽  
Deep Levels ◽  
High Temperature Annealing ◽  
Implantation Damage ◽  
Transient Spectroscopy ◽  
P Type ◽  
Two Peaks ◽  
Dlts Spectra

The authors have investigated deep levels in the whole energy range of bandgap of 4H-SiC, which are generated by N+, P+, Al+ implantation, by deep level transient spectroscopy (DLTS). Ne+-implanted samples have been also prepared to investigate the pure implantation damage. In the n-type as-grown material, Z1/2 (Ec – 0.63 eV) and EH6/7 (Ec – 1.6 eV) are dominant deep levels. When the implant dose is low, seven peaks (IN1, IN3 ~ IN6, IN8, IN9) have emerged by implantation and annealing at 1000oC in the DLTS spectra from all n-type samples. After high-temperature annealing at 1700oC, however, most DLTS peaks disappeared, and two peaks, Z1/2 and EH6/7 survive. In the p-type as-grown material, D center (Ev + 0.40 eV) and HK4 (Ev + 1.4 eV) are dominant. When the implant dose is low, two peaks (IP1, IP3) have emerged by implantation and annealing at 1000oC, and four traps IP2, IP4 (Ev + 0.72 eV), IP7 (Ev + 1.3 eV), and IP8 (Ev + 1.4 eV) are dominant after annealing at 1700oC.

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