Implant-induced strain-relaxation in SiGe/Si layers

Author(s):  
N. David Theodore ◽  
Gordon Tam

SiGe is being extensively investigated for use in heterojunction bipolar-transistors (HBT) and high-speed integrated circuits. SiGe is typically used as an epitaxial base material in HBTs. To obtain extremely high-performance bipolar-transistors it is necessary to reduce the extrinsic base-resistance. This can be done by increasing the base-doping or by widening the base link-region by ion implantation. A problem that arises however with the use of implantation is that blanket implants have been found to enhance strain-relaxation of SiGe/Si. Strain relaxation will cause the bandgap-difference between Si and SiGe to decrease; this difference is maximum for a strained SiGe layer. The electrical benefits of using SiGe/Si arise largely from the presence of a significant bandgap-difference across the SiGe/Si interface. Strain relaxation reduces this benefit. Furthermore, once misfit or threading dislocations result (during strain-relaxation), the defects can give rise to recombination-generation in depletion regions of the device; high electrical leakage currents result.

Author(s):  
N. David Theodore ◽  
Donald Y.C Lie ◽  
J. H. Song ◽  
Peter Crozier

SiGe is being extensively investigated for use in heterojunction bipolar-transistors (HBT) and high-speed integrated circuits. The material offers adjustable bandgaps, improved carrier mobilities over Si homostructures, and compatibility with Si-based integrated-circuit manufacturing. SiGe HBT performance can be improved by increasing the base-doping or by widening the base link-region by ion implantation. A problem that arises however is that implantation can enhance strain-relaxation of SiGe/Si.Furthermore, once misfit or threading dislocations result, the defects can give rise to recombination-generation in depletion regions of semiconductor devices. It is of relevance therefore to study the damage and anneal behavior of implanted SiGe layers. The present study investigates the microstructural behavior of phosphorus implanted pseudomorphic metastable Si0.88Ge0.12 films on silicon, exposed to various anneals.Metastable pseudomorphic Si0.88Ge0.12 films were grown ~265 nm thick on a silicon wafer by molecular-beam epitaxy. Pieces of this wafer were then implanted at room temperature with 100 keV phosphorus ions to a dose of 1.5×1015 cm-2.


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.


1997 ◽  
Vol 18 (9) ◽  
pp. 426-428 ◽  
Author(s):  
R. Tang ◽  
J. Ford ◽  
B. Pryor ◽  
S. Anandakugan ◽  
P. Welch ◽  
...  

1991 ◽  
Vol 220 ◽  
Author(s):  
Maurizio Arienzo ◽  
James H. Comfort ◽  
Emmanuel F. Crabbé ◽  
David L. Marame ◽  
Subramanian S. Iyer ◽  
...  

ABSTRACTStrained layer growth of SiGe on Si by either Molecular Beam Epitaxy (MBE) or various methods of Chemical Vapor Deposition (CVD), including Limited Reaction Processing (LRP) and Ultra High Vacuum CVD (UHV/CVD) have been used to realize narrow bandgap base double heterojunction bipolar transistors (HBTs). This review paper will focus on the fabrication of high performance transistors, and on the material and process challenges facing the implementation of SiGe HBT technology. In particular, the use of SiGe alloys for bandgap engineering of bipolar devices and the development of self-aligned, epitaxial base bipolar device structures will be discussed, including the most recent accomplishment of 75 GHz ƒr heterojunction bipolar transistors, and the record sub-25 ps EC L ring oscillator delay. The design flexibility and trade-offs offered by SiGe heterojunction technology, like junction field/capacitance control, liquid nitrogen operation and complementary processes, arc also reviewed, to assess the leverage of a SiGe base bipolar technology in high speed circuits.


1998 ◽  
Vol 09 (02) ◽  
pp. 567-593 ◽  
Author(s):  
EIICHI SANO ◽  
KAZUO HAGIMOTO ◽  
YASUNOBU ISHII

High-speed integrated circuits (ICs) are essential for expanding the capacity of light-wave communications. InP-based heterostructure field effect transistors (HFETs) and heterojunction bipolar transistors (HBTs) are very promising for producing high-speed digital and analog ICs. This paper reviews the current status of InP-based lightwave communication ICs in terms of device, circuit, and packaging technologies. A successful 40-Gbit/s, 300-km optical fiber transmission using InP HFET ICs demonstrates the feasibility of the ICs. Furthermore, we estimate future IC performance based on the relationship between electron device figures-of-merit and IC speed. To keep up with the performance trend, technological problems, like inter- and intra-chip interconnections, have to be solved.


1998 ◽  
Vol 09 (02) ◽  
pp. 643-670 ◽  
Author(s):  
BIPUL AGARWAL ◽  
RAJASEKHAR PULLELA ◽  
UDDALAK BHATTACHARYA ◽  
DINO MENSA ◽  
QING-HUNG LEE ◽  
...  

Transferred-substrate heterojunction bipolar transistors (HBTs) have demonstrated very high bandwidths and are potential candidates for very high speed integrated circuit (IC) applications. The transferred-substrate process permits fabrication of narrow and aligned emitter-base and collector-base junctions, reducing the collector-base capacitance and increasing the device f max . Unlike conventional double-mesa HBTs, transferred-substrate HBTs can be scaled to submicron dimensions with a consequent increase in bandwidth. This paper introduces the concept of transferred-substrate HBTs. Fabrication process in the AlInAs/GaInAs material system is presented, followed by DC and RF performance. A demonstration IC is shown along with some integrated circuits in development.


2014 ◽  
Vol 778-780 ◽  
pp. 1009-1012 ◽  
Author(s):  
Shakti Singh ◽  
Nourhan El Sayed ◽  
Hazem Elgabra ◽  
Tamador ElBoshra ◽  
Maisam Wahbah ◽  
...  

SiC, a wide band gap semiconductor, is capable of robust operation at temperatures well above 600°C. SiC bipolar transistors are well suited for applications at high temperatures as, unlike MOSFET, it does not have a critical gate oxide, and hence oxide reliability at high temperatures is not an issue. In this paper, the design of optimized emitter coupled logic technology circuits using 4H-SiC bipolar transistors is presented. The circuits work over a wide range of temperatures and power supply voltages at high speeds, demonstrating the potential of robust high speed ECL integrated circuits in SiC for small-scale logic applications.


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