Investigation of Deep Levels In X-Ray Detector Material With Photo Induced Current Transient Spectroscopy (Picts)

1993 ◽  
Vol 302 ◽  
Author(s):  
C Eiche ◽  
M Fiederle ◽  
J Weese ◽  
D Maier ◽  
D Ebling ◽  
...  

ABSTRACTDeep levels have a great influence on the recombination behavior of the free carriers in semiconductors. For several years PICTS has been used to investigate the deep levels in high resistivity material such as GaAs or CdTe used in detector applications. An important feature of the PICTS measurements is the analysis of the current transients after pulse excitation. We propose using a new method based on Tikhonov regularization. This method was implemented in the program FTIKREG (Fast Tikhonov Regularization) by one of the authors. The superior resolution of the regularization method in comparison to conventional techniques is shown using simulated data. Moreover, the method is applied to investigate deep levels in CdTe:Cl, SI-GaAs and GaAs:Cr samples used for room temperature radiation detectors. A relation between deep level properties and detector performance is proposed.

Author(s):  
Nataliya Mitina ◽  
Vladimir Krylov

The results of an experiment to determine the activation energy of a deep level in a gallium arsenide mesastructure, obtained by the method of capacitive deep levels transient spectroscopy with data processing according to the Oreshkin model and Lang model, are considered.


2014 ◽  
Vol 997 ◽  
pp. 492-495
Author(s):  
Huan Cui ◽  
Li Wu Lu ◽  
Ling Sang ◽  
Bai He Chen ◽  
Zhi Wei He ◽  
...  

The deep levels of carbon doped high resistivity (HR) GaN samples grown by metal-organic chemical vapor deposition (MOCVD) has been investigated using thermally stimulated current (TSC) spectroscopy and high temperature (HT) Hall measurement. Two different thickness of 100 and 300 nm were used to be compared. It was found that four distinct deep levels by TSC and one deep level by HT Hall measurement were observed in both samples, which means great help for the decrease of leakage current and lifetime limitations of device utilizing the structure. The activation energy of these levels was calculated and their possible origins were also proposed. The low temperature traps, might be related to VN, 0.50 and 0.52eV related to incorporate a high level carbon, 0.57eV related to VGa, 0.59eV related to CGaor NGa, 0.91 and 0.97eV related to interstitial N1.


2006 ◽  
Vol 911 ◽  
Author(s):  
Anna Cavallini ◽  
Antonio Castaldini ◽  
Filippo Nava ◽  
Paolo Errani ◽  
Vladimir Cindro

AbstractWe investigated the electronic levels of defects introduced in 4H-SiC α-particle detectors by irradiation with 1 MeV neutrons up to a fluence equal to 8x1015 n/cm2. As well, we investigated their effect on the detector radiation hardness. This study was carried out by deep level transient spectroscopy (DLTS) and photo-induced current transient spectroscopy (PICTS). As the irradiation level approaches fluences in the order of 1015 n/cm2, the material behaves as highly resistive due to a very great compensation effect but the diodes are still able to detect with a acceptably good charge collection efficiency (CCE) equal to 80%. By further increasing fluence, CCE decreases reaching the value of ≈ 20% at fluence of 8x1015 n/cm2.The dominant peaks in the PICTS spectra occur in the temperature range [400, 700] K. Enthalpy, capture cross-section and order of magnitude of the density of such deep levels were calculated. In the above said temperature range the deep levels associated to the radiation induced defects play the key role in the degradation of the CCE. Two deep levels at Et = 1.18 eV and Et = 1.50 eV are likely to be responsible of such dramatic decrease of the charge collection efficiency. These levels were reasonably associated to an elementary defect involving a carbon vacancy and to a defect complex involving a carbon and a silicon vacancy, respectively.


2010 ◽  
Vol 645-648 ◽  
pp. 759-762
Author(s):  
Koutarou Kawahara ◽  
Giovanni Alfieri ◽  
Michael Krieger ◽  
Tsunenobu Kimoto

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.


Sign in / Sign up

Export Citation Format

Share Document