Oxygen Precipitation Studies for N-Type and Epitaxial Silicon Substrates During Simulated Cmos Cycles by Synchrotron Section Topography

1986 ◽  
Vol 71 ◽  
Author(s):  
T. Tuomi ◽  
S. Hahn ◽  
M. Tilli ◽  
C.-C. D. Wong ◽  
O. Borland

AbstractSynchrotron section topography is applied to the study of silicon wafers pulled out froma simulated advanced CMOS twin-tub process. Substrates are heavily doped with antimony and phosphorus. For comparison also high-resistivity samples are studied. Prior to epi deposition of arsenic doped layers some wafers are subjected to a three-step intrinsic gettering cycle.Section topographs show that in the lightly doped samples a denuded zone is formed by the CMOS process itself in contrast with the heavily doped ones in which the intrinsic gettering is needed.

1986 ◽  
Vol 1 (5) ◽  
pp. 693-697 ◽  
Author(s):  
W. Wijaranakula ◽  
P.M. Burke ◽  
L. Forbes

As-received P/P + (100) epitaxial silicon wafers were heat treated using the one-, two-, and three-step internal gettering heat treatment cycles in wet oxygen, dry oxygen, and nitrogen ambients. The results indicate that ambients have an effect on the growth of bulk defects and denuded zone formation in the epitaxial silicon wafers.


2015 ◽  
Vol 242 ◽  
pp. 218-223
Author(s):  
Peng Dong ◽  
Xing Bo Liang ◽  
Da Xi Tian ◽  
Xiang Yang Ma ◽  
De Ren Yang

We report a strategy feasible for improving the internal gettering (IG) capability of iron (Fe) for n/n+ epitaxial silicon wafers using the heavily arsenic (As)-doped Czochralski (CZ) silicon wafers as the substrates. The n/n+ epitaxial silicon wafers were subjected to the two-step anneal of 650 °C/16 h + 1000 °C/16 h following the rapid thermal processing (RTP) at 1250 °C in argon (Ar) or nitrogen (N2) atmosphere. It is found that the prior RTP in N2 atmosphere exhibits much stronger enhancement effect on oxygen precipitation (OP) in the substrates than that in Ar atmosphere, thereby leading to a better IG capability of Fe contamination on the epitaxial wafer. In comparison with the RTP in Ar atmosphere, the one in N2 atmosphere injects not only vacancies but also nitrogen atoms of high concentration into the heavily As-doped silicon substrate. The co-action of vacancy and nitrogen leads to the enhanced OP in the substrate and therefore the better IG capability for the n/n+ epitaxial silicon wafer.


Manufacturing ◽  
2003 ◽  
Author(s):  
Iqbal K. Bansal

Direct wafer bonding (DWB) is an operation of ultra-fine alignment, joining and thermal bonding of two silicon wafers. The first silicon wafer “handle” substrate is a Czochralski (<CZ>) substrate with N+ arsenic dopant with very low bulk resistivity, whereas second wafer “device” is a float-zone (<FZ>) having extremely high resistivity N-phosphorus dopant. Prior to the joining step, silicon wafers are chemically cleaned in order to minimize surface contamination. The wafer surface is “hydrophobic” which is achieved using an insitu oxide etching process. The surface quality is also characterized in terms of sub-micron light point defects (LPD’s) counts and haze concentration using a laser beam scanning system. After chemical clean, none of the LPD’s counts is greater than 1.0 μ size. The joining step is performed in a Class 100 or better environment by employing a commercial joiner. Then, thermal bonding operation is carried out by employing an extended stream oxidation cycle at elevated temperatures. Typical failure modes of DWB are misalignment errors and “voided” or “disbonded” regions. The area of “voided” regions for each bonded pair is determined by employing a scanning acoustic microscope. Detailed product throughtput and yield data are presented in this paper. A spreading resistivity profile (SRP) system is employed for accurate measurement of doping carrier concentration as a function of the depth. The superior uniformity for capacitance-voltage characteristics of a Si-Si bonded wafer versus an inverse epitaxial silicon wafer substrate is shown in terms of the device performance. The applications of silicon-direct wafer bonded substrates provide a quantum jump in the device electrical performance of PIN diodes.


1986 ◽  
Vol 1 (5) ◽  
pp. 698-704 ◽  
Author(s):  
W. Wijaranakula ◽  
P.M. Burke ◽  
L. Forbes ◽  
J.H. Matlock

Substrate material used for fabrication of P/P + epitaxial silicon wafers was preannealed at 650 °C in nitrogen ambient prior to the epitaxial deposition process for various times up to 300 min. The substrate material originated from a characterized crystal ingot. The results show that annealing before epitaxial deposition can preserve oxide precipitate nuclei from dissolution during the epitaxial deposition process. Additional postepitaxial annealing at 750 °C further enhances the growth of bulk defects.


2007 ◽  
Vol 1035 ◽  
Author(s):  
Seol Hee Choi ◽  
Chan Hyoung Kang

AbstractHighly c-axis oriented, dense, and fine-grained polycrystalline ZnO films with smooth surface and high resistivity were deposited on 4 inch silicon wafers by employing ZnO targets in a radio-frequency (RF) magnetron sputtering system. By changing applied RF power, substrate temperature and O2/Ar gas ratio, the optimum process parameters were found to be 150 W, 200 °C and 30/70, respectively. Applying the ZnO films deposited under these optimum conditions, surface acoustic wave (SAW) devices of ZnO/IDT/SiO2/Si structure were fabricated by conventional photolithography and etching processes. The interdigital transducers (IDT), made of the aluminum deposited by DC magnetron sputter, were patterned as 2.5/2.5 μm of finger width/spacing. Another type of SAW filter of IDT/ZnO/diamond/Si structure was fabricated. In this structure, high-quality nanocrystalline diamond (NCD) films were deposited on 4 inch silicon wafers by direct current (DC) plasma assisted chemical vapor deposition method using H2-CH4 mixture as precursor gas. On the top of the diamond films, ZnO films were deposited under the optimum conditions. The aluminum IDT pattern was fabricated on the ZnO/diamond layered films. The characteristics of the fabricated SAW devices were evaluated in terms of center frequency, insertion loss, and wave propagation velocity.


1995 ◽  
Vol 66 (20) ◽  
pp. 2709-2711 ◽  
Author(s):  
Masaki Aoki ◽  
Toru Itakura ◽  
Nobuo Sasaki

1988 ◽  
Vol 116 ◽  
Author(s):  
A. Georgakilas ◽  
M. Fatemi ◽  
L. Fotiadis ◽  
A. Christou

AbstractOne micron thick AlAs/GaAs structures have been deposited by molecular beam epitaxy onto high resistivity silicon substrates. Subsequent to deposition, it is shown that Excimer laser annealing up to 120mJ/cm2 at 248nm improves the GaAs mobility to approximately 2000cm2 /v-s. Dislocation density, however, did not decrease up to 180mJ/cm2 showing that improvement in transport properties may not be accompanied by an associated decrease in dislocation density at the GaAs/Si interface.


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