GeSi Infrared Detectors Using Selective Deposition

1995 ◽  
Vol 402 ◽  
Author(s):  
R. Strong ◽  
D. W. Greve ◽  
M. M. Weeks

AbstractHeterojunction p++ GeSi / Si internal photoemission (HIP) detectors deposited by ultra high vacuum chemical vapor deposition (UHV/CVD) were investigated as alternatives to silicide Schottky-barrier type detectors for infrared focal plane arrays. HIP structures were grown using SiH4, GeH4, and B2H6 source gases on (100) p- Si substrates patterned with thermal oxide windows. Selective epitaxy was maintained over a range of boron concentrations (6×1019 – 6.5×1020 cm-3) and Ge fractions (0.38–0.50), and a maximum selective thickness of ~300Å was determined for silicon growth at 550°C. These structures were fabricated into IR detectors using techniques compatible with standard Si focal plane array processing technology. Photoresponse data were analyzed according to the modified Fowler equation, indicating cut-off wavelengths of 5–12 (μm) and Cl values of 8–21 (%/eV) depending on sample parameters. I(V) characteristics were also measured at various temperatures, yielding electrical barrier heights consistent with optical measurements.

1995 ◽  
Vol 402 ◽  
Author(s):  
P. E. Hompson ◽  
M. Weeks ◽  
P. Tedrow ◽  
K. Hobart

AbstractEncouraging results have been reported for discrete heterojunction internal photoemission (HIP) infrared (IR) detectors composed of heavily boron doped Si1−3Gex layers on Si. We desired to build on those results and fabricate 640×480 IR focal plane arrays on 100 mm Si substrates, suitable for commercial microelectronic processing. In this paper we discuss the growth issues for growing these structures by molecular beam epitaxy. Since the wafers had already undergone processing and some had PtSi contacts, the growth temperature was constrained to be no greater than 600 °C. Precise temperature control was obtained by calibrating an optical pyrometer with a thermocouple embedded in the substrate heater assembly, which was calibrated using the eutectic emperatures of Au/Si and Al/Si. The final step of the cleaning process was a 1% HF dip/ spin dry, which resulted in a H-terminated surface. The H was removed at 550 °C in vacuum prior to rowth. The growth of the B-doped SiGe layer was done at 350 °C to minimize segregation and diffusion of the Ge and B. Doping levels of 2×1020/cm3 were obtained with near 100% activation. Using Si0.35, doped with 2×1020 B/cm3, a cut-off wavelength of 11.1 μm and an emission coefficient of 19.8 %/eV were obtained for discrete detectors. Preliminary results from the detector arrays show full functionality in the spectral range of 6.1 to 12.8 μm.


1995 ◽  
Vol 395 ◽  
Author(s):  
John Kouvetakis ◽  
Jeffrey McMurran ◽  
David B. Beach ◽  
David J. Smith

ABSTRACTWe have demonstrated growth of crystalline GaN on Si substrates by using, for the first time, a novel inorganic precursor Cl2GaN3 and ultra-high-vacuum chemical vapor deposition techniques. Cross-sectional electron microscopy of the highly conformal films showed columnar growth of wurtzite GaN while Auger and RBS oxygen- and carbon-resonance spectroscopies showed that the films were pure and highly homogeneous. In addition to the high growth rates of 70–500 Å per minute, the low deposition temperature of 550–700 °C, and the nearly perfect GaN stoichiometry that we obtain, another notable advantage of our method is that it provides a carbon-free growth environment which is compatible with p-doping processes.


1997 ◽  
Vol 3 (S2) ◽  
pp. 457-458
Author(s):  
D. Chandrasekhar ◽  
David J. Smith ◽  
J. Kouvetakis

Group IV based alloys have received considerable attention in recent years, because of the possibility to tailor the band gap of the material system with respect to that of Si. Significant results have already been achieved with Si-Ge system, where the band gap of pseudomorphic Si1-xGex alloys is smaller than that of Si. Introduction of C onto substitutional lattice sites in Si has been proposed as a possible alternate method for tailoring the electronic properties of Si. Carbon incorporation into Si substitutionally could result in alloys whose band gap would be a function of carbon concentration and lie between the values for silicon (E =1.1 eV) and β-SiC (Eg = 2.3 eV). However, due to the low-equilibrium solubility limit of C in Si, 3.5x1017cm−3 at the eutectic temperature, highly supersaturated and metastable layers are essential to significantly alter strain and electrical properties of the alloys.In our present study, we have synthesized and characterized Si1-yCy (0.04 < y < 0.20) films grown on (001) Si substrates by ultra-high vacuum chemical vapor deposition at 625°C.


2005 ◽  
Vol 483-485 ◽  
pp. 205-208 ◽  
Author(s):  
Motoi Nakao ◽  
Hirofumi Iikawa ◽  
Katsutoshi Izumi ◽  
Takashi Yokoyama ◽  
Sumio Kobayashi

200 mm wafer with 3C-SiC/SiO2/Si structure has been fabricated using 200 mm siliconon- insulator (SOI) wafer. A top Si layer of 200 mm SOI wafer was thinned down to approximately 5 nm by sacrificial oxidization, and the ultrathin top Si layer was metamorphosed into a 3C-SiC seed layer using a carbonization process. Afterward, an epitaxial SiC layer was grown on the SiC seed layer with ultra-high vacuum chemical vapor deposition. A cross-section transmission electron microscope indicated that a 3C-SiC seed layer was formed directly on the buried oxide layer of 200 mm wafer. The epitaxial SiC layer with an average thickness of approximately 100 nm on the seed was recognized over the entire region of the wafer, although thickness uniformity of the epitaxial SiC layer was not as good as that of SiC seed layer. A transmission electron diffraction image of the epitaxial SiC layer showed a monocrystalline 3C-SiC(100) layer with good crystallinity. These results indicate that our method enables to realize 200 mm SiC wafers.


1991 ◽  
Vol 6 (9) ◽  
pp. 1913-1918 ◽  
Author(s):  
Jiong-Ping Lu ◽  
Rishi Raj

Chemical vapor deposition (CVD) of titanium oxide films has been performed for the first time under ultra-high vacuum (UHV) conditions. The films were deposited through the pyrolysis reaction of titanium isopropoxide, Ti(OPri)4, and in situ characterized by x-ray photoelectron spectroscopy (XPS) and Auger electron spectroscopy (AES). A small amount of C incorporation was observed during the initial stages of deposition, through the interaction of precursor molecules with the bare Si substrate. Subsequent deposition produces pure and stoichiometric TiO2 films. Si–O bond formation was detected in the film-substrate interface. Deposition rate was found to increase with the substrate temperature. Ultra-high vacuum chemical vapor deposition (UHV-CVD) is especially useful to study the initial stages of the CVD processes, to prepare ultra-thin films, and to investigate the composition of deposited films without the interference from ambient impurities.


2019 ◽  
Vol 507 ◽  
pp. 113-117 ◽  
Author(s):  
Jiaqi Wang ◽  
Limeng Shen ◽  
Guangyang Lin ◽  
Jianyuan Wang ◽  
Jianfang Xu ◽  
...  

1986 ◽  
Vol 67 ◽  
Author(s):  
N. Otsuka ◽  
C. Choi ◽  
Y. Nakamura ◽  
S. Nagakura ◽  
R. Fischer ◽  
...  

ABSTRACTRecent studies have shown that high quality GaAs films can be grown by MBE on Si substrates whose surfaces are slightly tilted from the (100) plane. In order to investigate the effect of the tilting of substrate surfaces on the formation of threading dislocations, the GaAs/Si epitaxial interfaces have been observed with a 1 MB ultra-high vacuum, high voltage electron microscope. Two types of misfit dislocations, one with Burgers vectors parallel to the interface and the other with Burgers vectors inclined from the interface, were found in these epitaxial interfaces. The observation of crosssectional samples perpendicular to each other has shown that the tilting of the substrate surface directly influences the generation of these two types of misfit dislocations. The mechanism of the reduction of threading dislocations by the tilting of the substrate surface is discussed based on these observations.


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