Shaping of Dopant Concentration Profiles in Silicon by Multiple–Pulse Laser Processing

1981 ◽  
Vol 4 ◽  
Author(s):  
C Hill ◽  
A L Butler ◽  
J A Daly

ABSTRACTOver the past ten years, the performance of bipolar transistors in high speed integrated circuits has been steadily improved by fully exploiting the complex solid state diffusion behaviour of dopants in silicon to make successively closer approaches to the ideal dopant profiles in the emitter and base regions of the transistor. Further optimisation requires a new approach, and in this paper an entirely new method of shaping the dopant profiles by exploiting the large ratio (about 108) of diffusion coefficients in liquid and solid silicon near the melting point is described Melting is effected by irradiation with a homogenised pulse from a Q-switched ruby laser. Completely new features of the technique are the controllable fabrication of both quasi–Gaussian and quasi-rectangular dopant profiles independent of dopant (arsenic or boron), dopant concentration (1013−1016atom cm−2) or presence of other dopants. This allows for the first time independent optimisation of emitter profile shape, emitter doping level, and base profile in bipolar transistor structures.

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.


2015 ◽  
Vol 16 (1) ◽  
pp. 221-229
Author(s):  
S.P. Novosyadlyy ◽  
A.M. Bosats'kyy

Reducing the size of silicon devices is accompanied by an increase in the effective rate of electrons,  decrease transit time and the transition to a ballistic work.Power consumption is reduced too. Formation of large integrated circuits structures onSi-homotransition reduces their frequency range and performance.Nowadaysproposed several new types of devices and technologies forming of large integrated circuits structures that based on high speeds and mobility of electrons in GaAs, and  small size structures.These include, for example, the heterostructure field-effect transistors on a segmented doping, bipolar transistors with wide-emitter, transistor with soulful base, vertical ballistic transistors, devices with flat-doped barriers and hot electron transistors as element base of modern high-speed large integrated circuits.In this article we consider graded-gap technology formatting as bipolar and field-effect transistors, which are the basis of modern high-speedof large integrated circuits structures.


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.


1990 ◽  
Vol 11 (4) ◽  
pp. 149-152 ◽  
Author(s):  
P.J. Van Wijnen ◽  
R.D. Gardner

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.


MRS Bulletin ◽  
1988 ◽  
Vol 13 (10) ◽  
pp. 36-43 ◽  
Author(s):  
A.S. Jordan ◽  
J.M Parsey

From a commercial viewpoint, gallium arsenide (GaAs) is currently the leading member of the III-V compound family. Oriented substrates, cut and polished from single-crystal boules, form the materials foundation for a rapidly maturing technology of high speed and high frequency electronic devices and circuits. The initial thrust of GaAs applications was in high powered lasers and light-emitting diodes (LEDs) fabricated on n-type (Si-doped) GaAs wafers grown by the horizontal Bridgman technique. One of the important benefits of using GaAs is the high electron mobility compared to Si. This property has driven the development of low noise and power field-effect transistors (FETs) for microwave applications. The semi-insulating substrate requirement (>107 Ω-cm) was initially met by chromium doping. Currently, the interest is focused on MMIC (microwave monolithic integrated circuits), MIMIC (millimeter microwave ICs), analog ICs for lightwave transmitters and receivers, and digital ICs. The digital circuits have been realized with ion-implanted FETs, selectively doped heterostructure transistors (SDHTs), and heterostructure bipolar transistors (HBTs). Presently, most of the semi-insulating (SI) material processed by the industry is nominally undoped, and grown by the liquid encapsulated Czochralski (LEC) technique. The SI behavior is attained via a delicate balance of deep EL2 donors and carbon acceptors, avoiding chromium in order to eliminate the anomalous out-diffusion and type-conversion associated with this dopant.GaAs wafers up to 4 inches in diameter, with electrical properties homogenized by whole ingot annealing, are currently available from U.S. domestic and overseas suppliers. However, the overall quality is compromised by the large dislocation densities, varying 104 – 105/cm2.


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