Excess Carrier Lifetime Measurement for Plasma-Etched GaN by the Microwave Photoconductivity Decay Method

2007 ◽  
Vol 46 (1) ◽  
pp. 35-39 ◽  
Author(s):  
Hideki Watanabe ◽  
Masashi Kato ◽  
Masaya Ichimura ◽  
Eisuke Arai ◽  
Masakazu Kanechika ◽  
...  
2002 ◽  
Vol 80 (23) ◽  
pp. 4390-4392 ◽  
Author(s):  
Masaya Ichimura ◽  
Atsushi Tada ◽  
Eisuke Arai ◽  
Hiroyuki Takamatsu ◽  
Shingo Sumie

2007 ◽  
Vol 46 (8A) ◽  
pp. 5057-5061 ◽  
Author(s):  
Masashi Kato ◽  
Masahiko Kawai ◽  
Tatsuhiro Mori ◽  
Masaya Ichimura ◽  
Shingo Sumie ◽  
...  

1997 ◽  
Vol 70 (13) ◽  
pp. 1745-1747 ◽  
Author(s):  
M. Ichimura ◽  
H. Tajiri ◽  
Y. Morita ◽  
N. Yamada ◽  
A. Usami

2009 ◽  
Vol 1153 ◽  
Author(s):  
Jun Wang ◽  
Mahdi Farrokh Baroughi ◽  
Mariyappan Shanmugam ◽  
Roohollah Samadzadeh-Tarighat ◽  
Siva Sivoththaman ◽  
...  

AbstractSurface passivation of silicon substrates using atomic layer deposited Al2O3 and HfO2 thin films are assessed. Al2O3 and HfO2 dielectric layers with various thicknesses were deposited on both sides of n-type (100) FZ-Si substrates (resistivity 4 – 6 Ω-cm) at 200°C by atomic layer deposition (ALD) system. The effective excess carrier lifetime of as-deposited oxide/Si/oxide structure was measured by microwave-photoconductivity-decay (MWPCD) measurement technique and it was observed that the thicker ALD dielectrics lead to higher effective excess carrier lifetime and better surface passivation. The measurements showed average excess carrier lifetime values of 302 μs and 347 μs for as-deposited Al2O3 and HfO2 passivated Si substrates with 150 ALD cycles, respectively. MWPCD and capacitance-voltage (C-V) measurements suggest that as-deposited ALD HfO2 layer leads to a better surface passivation compared to as-deposited ALD Al2O3 layer. Further, the results suggest that there exist fixed negative charges in the bulk of the ALD dielectrics and this contributes to the field effect passivation of the silicon surfaces.


2012 ◽  
Vol 717-720 ◽  
pp. 305-308 ◽  
Author(s):  
Atsushi Yoshida ◽  
Masashi Kato ◽  
Masaya Ichimura

We obtained excess carrier lifetime maps by the microwave photoconductivity decay (µ-PCD) method in a free-standing n-type 3C-SiC wafer, and then we compared the lifetime maps with distributions of strains and defects observed by the optical microscopy and the Raman spectroscopy. We found that the excess carrier lifetimes are short in a strained region in 3C-SiC, which indicates that structural defects exist around a strained region.


2005 ◽  
Vol 44 (12) ◽  
pp. 8333-8339 ◽  
Author(s):  
Tatsuhiro Mori ◽  
Masashi Kato ◽  
Hideki Watanabe ◽  
Masaya Ichimura ◽  
Eisuke Arai ◽  
...  

2006 ◽  
Vol 21 (6) ◽  
pp. 771-774 ◽  
Author(s):  
Yanqiu Lv ◽  
Nili Wang ◽  
Chunquan Zhuang ◽  
Ping Li ◽  
Bing Han ◽  
...  

2010 ◽  
Vol 645-648 ◽  
pp. 207-210 ◽  
Author(s):  
Yoshinori Matsushita ◽  
Masashi Kato ◽  
Masaya Ichimura ◽  
Tomoaki Hatayama ◽  
Takeshi Ohshima

We measured the excess carrier lifetimes in as-grown and electron irradiated p-type 4H-SiC epitaxial layers with the microwave photoconductivity decay (-PCD) method. The carrier lifetime becomes longer with excitation density for the as-grown epilayer. This dependence suggests that e ≥h for the dominant recombination center, where e andh are capture cross sections for electrons and holes, respectively. In contrast, the carrier lifetime does not depend on the excitation density for the sample irradiated with electrons at an energy of 160 keV and a dose of 1×1017 cm-2. This may be due to the fact that recombination centers with e <<h were introduced by the electron irradiation or due to the fact that the acceptor concentration was decreased significantly by the irradiation.


2004 ◽  
Vol 831 ◽  
Author(s):  
Masashi Kato ◽  
Hideki Watanabe ◽  
Masaya Ichimura ◽  
Eisuke Arai

ABSTRACTWe have measured excess carrier lifetimes in GaN with various doping concentrations and surface conditions by the microwave photoconductivity decay method. GaN samples were grown by metalorganic chemical vapor deposition (MOCVD) without intentional doping and with Si doping or Mg doping on a-face sapphire substrates. By using the microwave photoconductivity decay method, we obtained 1/e excess carrier lifetimes of larger than 50 μs for the Si doped and undoped GaN and of less than 10 μs for the Mg doped GaN. We changed surface conditions for the samples by the inductively coupled plasma (ICP) etching and investigated effects of surface conditions on the carrier recombination behavior. The ICP etching has negligible effects on carrier lifetime in the Si doped GaN. On the other hand, in the undoped GaN, the ICP etching lengthened the carrier lifetime compared with the as-grown sample. On the contrary, the ICP etching shortened the carrier lifetime in the Mg doped GaN. The ICP etching seems to form hole traps and recombination centers at GaN surfaces and thus the carrier lifetime became longer in the undoped GaN and shorter in the Mg doped GaN.


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