Very-high-speed silicon bipolar transistors with in-situ doped polysilicon emitter and rapid vapor-phase doping base

1995 ◽  
Vol 42 (3) ◽  
pp. 406-412 ◽  
Author(s):  
T. Uchino ◽  
T. Shiba ◽  
T. Kikuchi ◽  
Y. Tamaki ◽  
A. Watanabe ◽  
...  
2021 ◽  
Vol 13 (3) ◽  
pp. 1505
Author(s):  
Ignacio Menéndez Pidal ◽  
Jose Antonio Mancebo Piqueras ◽  
Eugenio Sanz Pérez ◽  
Clemente Sáenz Sanz

Many of the large number of underground works constructed or under construction in recent years are in unfavorable terrains facing unusual situations and construction conditions. This is the case of the subject under study in this paper: a tunnel excavated in evaporitic rocks that experienced significant karstification problems very quickly over time. As a result of this situation, the causes that may underlie this rapid karstification are investigated and a novel methodology is presented in civil engineering where the use of saturation indices for the different mineral specimens present has been crucial. The drainage of the rock massif of El Regajal (Madrid-Toledo, Spain, in the Madrid-Valencia high-speed train line) was studied and permitted the in-situ study of the hydrogeochemical evolution of water flow in the Miocene evaporitic materials of the Tajo Basin as a full-scale testing laboratory, that are conforms as a whole, a single aquifer. The work provides a novel methodology based on the calculation of activities through the hydrogeochemical study of water samples in different piezometers, estimating the saturation index of different saline materials and the dissolution capacity of the brine, which is surprisingly very high despite the high electrical conductivity. The circulating brine appears unsaturated with respect to thenardite, mirabilite, epsomite, glauberite, and halite. The alteration of the underground flow and the consequent renewal of the water of the aquifer by the infiltration water of rain and irrigation is the cause of the hydrogeochemical imbalance and the modification of the characteristics of the massif. These modifications include very important loss of material by dissolution, altering the resistance of the terrain and the increase of the porosity. Simultaneously, different expansive and recrystallization processes that decrease the porosity of the massif were identified in the present work. The hydrogeochemical study allows the evolution of these phenomena to be followed over time, and this, in turn, may facilitate the implementation of preventive works in civil engineering.


1999 ◽  
Vol T79 (1) ◽  
pp. 318 ◽  
Author(s):  
W. Kaplan ◽  
J. Pejnefors ◽  
M. Linder ◽  
M. Sand?n ◽  
T. E. Karlin ◽  
...  

1989 ◽  
Vol 146 ◽  
Author(s):  
Fred Ruddell ◽  
Colin Parkes ◽  
B Mervyn Armstrong ◽  
Harold S Gamble

ABSTRACTThis paper describes a LPCVD reactor which was developed for multiple sequential in-situ processing. The system is capable of rapid thermal processing in the presence of plasma stimulation and has been used for native oxide removal, plasma oxidation and silicon deposition. Polysilicon layers produced by the system are incorporated into N-P-N polysilicon emitter bipolar transistors. These devices fabricated using a sequential in-situ plasma clean-polysilicon deposition schedule exhibited uniform gains limited to that of long single crystal emitters. Devices with either plasma grown or native oxide layers below the polysilicon exhibited much higher gains. The suitability of the system for sequential and limited reaction processing has been established.


1990 ◽  
Vol 01 (03n04) ◽  
pp. 245-301 ◽  
Author(s):  
M.F. CHANG ◽  
P.M. ASBECK

Recent advances in communication, radar and computational systems demand very high performance electronic circuits. Heterojunction bipolar transistors (HBTs) have the potential of providing a more efficient solution to many key system requirements through intrinsic device advantages than competing technologies. This paper reviews the present status of GaAs and InP-based HBT technologies and their applications to digital, analog, microwave and multifunction circuits. It begins with a brief review of HBT device concepts and critical epitaxial growth parameters. Issues important for device modeling and fabrication technologies are discussed. The paper then highlights the performance and the potential impact of HBT devices and integrated circuits in various application areas. Key prospects for future HBT development are also addressed.


2003 ◽  
Vol 3 (2) ◽  
pp. 31-38 ◽  
Author(s):  
J.-S. Rieh ◽  
K.M. Watson ◽  
F. Guarin ◽  
Zhijian Yang ◽  
Ping-Chuan Wang ◽  
...  

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