Mechanism of Dose-Rate Dependence of Electrical Activation in Ion-Implanted GaAs

1992 ◽  
Vol 279 ◽  
Author(s):  
Toshihiko Kanayama ◽  
Hisao Tanoue

ABSTRACTTo elucidate the mechanism of dose rate (DR) dependence of electrical activation, following two questions are investigated; why the amount of damage remaining after ion bombardment depends on DR and why it affects the electrical activation after high temperature annealing. From the observation that the DR dependence scales with temperature, the activation energy of recovery during ion irradiation has been estimated to be 0.75 and 1.0 eV. A higher DR suppresses the recovery and results in more damage, which in turn delays the electrical activation of implanted impurities.

2009 ◽  
Vol 156-158 ◽  
pp. 493-498
Author(s):  
Ming Hung Weng ◽  
Fabrizio Roccaforte ◽  
Filippo Giannazzo ◽  
Salvatore di Franco ◽  
Corrado Bongiorno ◽  
...  

This paper reports a detailed study of the electrical activation and the surface morphology of 4H-SiC implanted with different doping ions (P for n-type doping and Al for p-type doping) and annealed at high temperature (1650–1700 °C) under different surface conditions (with or without a graphite capping layer). The combined use of atomic force microscopy (AFM), transmission electron microscopy (TEM), and scanning capacitance microscopy (SCM) allowed to clarify the crucial role played by the implant damage both in evolution of 4H-SiC surface roughness and in the electrical activation of dopants after annealing. The high density of broken bonds by the implant makes surface atoms highly mobile and a peculiar step bunching on the surface is formed during high temperature annealing. This roughness can be minimized by using a capping layer. Furthermore, residual lattice defects or precipitates were found in high dose implanted layers even after high temperature annealing. Those defects adversely affect the electrical activation, especially in the case of Al implantation. Finally, the electrical properties of Ni and Ti/Al alloy contacts on n-type and p-type implanted regions of 4H-SiC were studied. Ohmic behavior was observed for contacts on the P implanted area, whilst high resistivity was obtained in the Al implanted layer. Results showed a correlation of the electrical behavior of contacts with surface morphology, electrical activation and structural defects in ion-implanted, particularly, Al doped layer of 4H-SiC.


2010 ◽  
Vol 645-648 ◽  
pp. 783-786
Author(s):  
Tatsunori Sugimoto ◽  
Masataka Satoh ◽  
Tohru Nakamura ◽  
K. Mashimo ◽  
Hiroshi Doi ◽  
...  

The impact of CF4 plasma treatment on the surface roughening of SiC has been investigated for N ion implanted SiC(0001) which is implanted with the energy range from 15 to 120 keV at a dose of 9.2 x 1014/cm2. The N ion implanted sample, which is processed by CF4 plasma, shows small surface roughness of 1.6 nm after annealing at 1700 oC for 10 min, while the sample without CF4 plasma treatment shows the large surface roughness (6.6nm) and micro step structure. XPS measurements reveals that CF4 plasma treatment is effective to dissolved the residual oxide on the surface of SiC which is not removed by BHF acid of SiO2 layer on SiC. It is strongly suggested that the formation of micro step structure with the increase of the surface roughness is promoted by the residual oxide such as SiCOx, on SiC.


2006 ◽  
Vol 912 ◽  
Author(s):  
Amitabh Jain

AbstractUltra-high temperature annealing is emerging as a promising technique for annealing ion implanted layers with a view to maximizing electrical activation while minimizing dopant diffusion. In order to ensure successful implementation, several materials-related problems have been under study. Since the time scale of the process is short, diffusion in the amorphous phase may dominate the final profile. In general, the residual disorder after anneal can be higher than with current anneal processes. However, the short time scale of the process curtails the opportunity for movement of dislocations into regions where the electrical behavior of a device would be affected. An additional effect of the limited time scale is the ability of silicon to plasto-elastically support the high strain-rates that may arise during the anneal.


2014 ◽  
Vol 53 (5S1) ◽  
pp. 05FC08 ◽  
Author(s):  
Akihiro Hashimoto ◽  
Yasuyuki Kaneno ◽  
Satoshi Semboshi ◽  
Hiroaki Yoshizaki ◽  
Yuichi Saitoh ◽  
...  

1999 ◽  
Vol 595 ◽  
Author(s):  
M. Kuball ◽  
J.M. Hayes ◽  
T. Suski ◽  
J. Jun ◽  
H.H. Tan ◽  
...  

AbstractWe have investigated the high-pressure high-temperature annealing of Mg/P-implanted GaN films using visible and ultraviolet (UV) micro-Raman spectroscopy. The results illustrate the use of Raman spectroscopy to monitor processing of GaN where fast feedback is required. The structural quality and the stress in ion-implanted GaN films was monitored in a 40nm-thin surface layer of the sample as well as averaged over the sample layer thickness. We find the nearly full recovery of the crystalline quality of ion-implanted GaN films after annealing at 1400-1500°C under nitrogen overpressures of 1.5GPa. No significant degradation effects occurred in the GaN surface layer during the annealing. The high nitrogen overpressures proved very effective in preventing the nitrogen out-diffusion from the GaN surface. Stress introduced during the annealing was monitored. Raman spectra of ion-implanted GaN films were investigated at different temperatures and excitation wavelengths to study the GaN phonon density of states.


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