BASE COMPOSITION EFFECTS STUDY ON NBR CURRENT AND CURRENT GAIN IN SiGe HBT

2013 ◽  
Vol 27 (19) ◽  
pp. 1350097 ◽  
Author(s):  
HOSSEN DAVOODI ◽  
HASSAN KAATUZIAN
Keyword(s):  
Bipolar Transistors ◽  
Current Gain ◽  
Sige Hbt ◽  
Base Current ◽  
Voltage Variation ◽  
Neutral Base ◽  
Heavily Doped ◽  
Frequency Behavior ◽  
20 Nm ◽  
First Time

In present study, SiGe Hetero-junction Bipolar Transistors (HBTs) performances are discussed based on both TCAD and analytical evaluations of the heavily doped base. It is demonstrated that neutral base recombination (NBR) current has significant effects on base current and hence current gain. An optimized Ge profile for 20 nm wide base of understudy structure, with 16% Germanium at EB edge and 24% at CB edge is concluded analytically, which improves DC and high frequency behavior. TCAD simulations reveal that for the specific structure and proposed profile, current gain is about 3500. It also exhibits ft and f max about 325 GHz and 192 GHz, respectively. In the next section for the first time, a comprehensive study of early voltage variation based on total Ge content and Ge grading in base is also presented. Forced base-emitter voltage and forced base current configurations are studied separately. NBR current has been analyzed under two different configuration and prospective guidelines are indicated.

Electrical Measurement of the Bandgap of N+ and P+ SiGe Formed by Ge Ion Implantation

1997 ◽  
Vol 500 ◽  
Author(s):  
Akira Nishiyama ◽  
Osamu Arisumi ◽  
Makoto Yoshimi
Keyword(s):  
Ion Implantation ◽  
Theoretical Calculation ◽  
Temperature Dependence ◽  
Electrical Measurement ◽  
Bipolar Transistors ◽  
Floating Body ◽  
High Dose ◽  
Base Current ◽  
Source Regions ◽  
Heavily Doped

ABSTRACTN+ and p+ SiGe layers were formed in the source regions of SOI MOSFETs in order to suppress the floating-body effects by means of high-dose Ge implantation. The bandgaps of the layers were evaluated by measuring the temperature dependence of the base current of the source/channel/drain lateral bipolar transistors. It has been found that the reductions of the bandgaps due to the SiGe formation by the Ge implantation were relatively small, compared to those obtained by the theoretical calculation for heavily doped SiGe. It was also found that the bandgap reduction was larger for n+ layers than that for p+ layers.

Shallow and Low-Resistive Ohmic Contacts to p-In0.53Ga0. 47As Based on Pd/Au and Pd/Sb Metallizations

1996 ◽  
Vol 427 ◽  
Author(s):  
P. Ressel ◽  
L. C. Wang ◽  
M. H. Park ◽  
P. W. Leech ◽  
G. K. Reeves ◽  
...  
Keyword(s):  
Heterojunction Bipolar Transistors ◽  
Ohmic Contacts ◽  
Bipolar Transistors ◽  
Base Layer ◽  
Current Gain ◽  
Depth Of Penetration ◽  
Annealing Conditions ◽  
Small Base ◽  
20 Nm ◽  
Contact Resistivities

AbstractInP/In0.53Ga0.47As heterojunction bipolar transistors with high current gain for optoelectronic applications place stringent requirements on the ohmic contact to the base layer of moderately doped (p < 1×1019 cm−3) In0.53Ga0.47As. Contact resistivity should be <l×10−6 Ωcm2 and low depth of penetration is necessary considering the small base thickness of approximately 100 nm. The authors have recently presented data on Pd/Zn/Au/LaB6/Au contacts on p-In0.53Ga0.47As (doped to 4×1018 cm−3) with low contact resistivities of l×10−6 Ωcm2. In this paper, details are given on the optimization of the contact composition and annealing conditions of the metallization that resulted in shallow and low-resistive contacts. Alternatively, it is shown that Au-free Pd/Zn/Sb/Pd contacts on p-In0.53Ga0.47As have exhibited even lower resistivities, i.e. 3-6×10−7 Ωcm2. Backside SIMS measurements revealed a depth of penetration as low as 20 nm for this contact scheme. Aging tests at temperatures of 300 - 400 °C have demonstrated that the electrical characteristics of both types of metallization were sufficiently stable to withstand the typical processing steps for device passivation.

The Use of Amorphous Silicon Emitters in Bipolar Transistors

1985 ◽  
Vol 49 ◽  
Author(s):  
M. Ghannam ◽  
J. Nijs ◽  
R. De Keersmaecker ◽  
R. Mertens
Keyword(s):  
Amorphous Silicon ◽  
Simple Technique ◽  
Bipolar Transistors ◽  
Degree Of Freedom ◽  
Current Gain ◽  
Base Resistance ◽  
Interface Recombination ◽  
Silicon Transistor ◽  
First Time

AbstractFor the first time an operating heterojunction bipolar silicon transistor has been realized with phosphorous doped amorphous silicon (a-Si) emitter. The deposition of a-Si is a relatively simple technique. The current gain (β) of 14 at a base Gummel Number (G.N.) of 1.35 1013 s/cm4 is higher than that obtained with normal diffused emitter bipolar transistors with the same G.N. for the base. This adds a degree of freedom to the design of bipolar structures according to the compromise between base resistance and current gainCrucial points that have to be looked at further are interface recombination at the a-Si/c-Si transition and emitter resistance.

The Role of the Si-SiO2 (CVD) Interface in Degradation Effects for High-Speed Bipolar Transistors

1995 ◽  
Vol 378 ◽  
Author(s):  
J.-Q. Lü ◽  
S. Schöttl ◽  
E. Stefanov ◽  
F. Koch ◽  
R. Mahnkopf ◽  
...  
Keyword(s):  
High Speed ◽  
Tunneling Current ◽  
Bipolar Transistors ◽  
Bipolar Transistor ◽  
Current Gain ◽  
Current Increase ◽  
Base Current ◽  
2D Simulation ◽  
Trap Assisted Tunneling ◽  
Emitter Junction

AbstractThe intent of the present work is to analyze device degradation and reliability in terms of their microscopic origins. The base-emitter junction of the advanced, “double-poly”, self-aligned bipolar transistor contacts the SiO2 sidewall spacer. During normal circuit operation, the base-emitter junction experiences a reverse bias which as a stress in time degrades the current gain of the transistor. Both a decrease of the gain, as well as an increase in the noise are observed. The forward base current increase as a function of stress time follows △IB ∼ tn. We present evidence that the defects are occurring at the Si-Si02 interface from perimeter to area comparisons. The weak temperature dependence of the forward base current in degraded transistors shows that trap-assisted tunneling current through the Si-SiO2 interface states is involved. The random-telegraph-signals observed for the first time in a silicon bipolar transistor are a direct identification of damage at the Si-SiO2 interface. 2D simulation of the potential and field near the interface allows us to show that damage can be expected.

TEM study of phosphorus-implanted pseudomorphic Si0.88Ge0.12 on Si(100)

1995 ◽  
Vol 53 ◽  
pp. 468-469
Author(s):  
N. David Theodore ◽  
Donald Y.C Lie ◽  
J. H. Song ◽  
Peter Crozier
Keyword(s):  
Integrated Circuits ◽  
Heterojunction Bipolar Transistors ◽  
Integrated Circuit ◽  
High Speed ◽  
Room Temperature ◽  
Strain Relaxation ◽  
Bipolar Transistors ◽  
Sige Hbt ◽  
Integrated Circuit Manufacturing ◽  
Microstructural Behavior

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.

Current gain variability in normal and I2L bipolar transistors

1979 ◽  
Vol 3 (4) ◽  
pp. 107
Author(s):  
A.B. Bhattacharyya ◽  
Subodh Jindal ◽  
Shankar Subramanian
Keyword(s):  
Bipolar Transistors ◽  
Current Gain
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