Hot Carrier Degradation of Gain in Bipolar Transistors

1995 ◽  
Vol 391 ◽  
Author(s):  
Isik C. Kizilyalli ◽  
Jeff D. Bude
Keyword(s):  
Impact Ionization ◽  
High Energy ◽  
Bipolar Transistors ◽  
Bipolar Transistor ◽  
Current Gain ◽  
Exponential Dependence ◽  
Hot Electron ◽  
Hot Carrier ◽  
Bicmos Technology ◽  
Doping Profiles

AbstractIn this paper hot carrier related aging of n-p-n bipolar transistors is investigated experimentally and theoretically to bring physical insight into the bipolar transistor hFE (common emitter current gain) degradation. Electrical stress experiments are performed on transistors with different base doping profiles at varying temperatures. Detailed process simulations are performed to determine the doping profiles of the base-emitter junction. Monte Carlo transport simulations are then performed at different temperatures and bias conditions to determine the electron and hole distribution functions in the baseemitter junction. AT&T's 0.8 μ.m BICMOS technology is used to fabricate the experimental bipolar transistor structures. For this non-self aligned technology we attribute hFE degradation to the presence of hot holes and secondary electrons which are generated by hot hole impact ionization. This feed-back due to impact ionization has a dominant effect on the high energy tails of the distribution of both holes and electrons even when the overall current multiplication is low. Simple hot electron energy transport models do not contain the complexity to properly describe ionization feedback and carrier heating, and are therefore inadequate. An exponential dependence of the transistor lifetime on BVEBO is deduced for constant voltage stress (Vstress < BVEBO) conditions, confirming the importance of secondaries in the process of degradation.

Vertical Bipolar Transistors and a Merged 3–D Vertical Bipolar—Mos Device in Recrystallized Polysilicon

1985 ◽  
Vol 53 ◽  
Author(s):  
J.C. Sturm ◽  
J.F. Gibbons
Keyword(s):  
Minority Carrier ◽  
Strong Dependence ◽  
Three Dimensional ◽  
Bipolar Transistors ◽  
Bipolar Transistor ◽  
Current Gain ◽  
Collector Current ◽  
Beam Laser ◽  
P Type ◽  
Mos Device

ABSTRACTThe minority carrier properties of shaped—beam laser-recrystallized polysilicon films have been studied, leading to the successful fabrication of vertical bipolar transistors in these films and to the demonstration of a novel three—dimensional mergedvertical bipolar—MOS device. Experiments with lateral transistors established a minority carrier diffusion length of 4 μm in p—type recrystallized films. Vertical bipolar npn transistors with a base—width of 0.2 μm were fabricated in 0.75–μm—thick films using a polysilicon emitter technology. The strong dependence of the gain of the transistors on hydrogen annealing steps is described. With an Ar:H plasma anneal to decrease base—emitter space—charge region recombination, a common—emitter current gain of 100 was possible. The bipolar transistor technology was then used to develop a 3—D fourterminal merged verticalbipolar—MOS device in a recrystallized film. It consists of the three terminals of a bipolar transistor plus a fourth underlying terminal which serves to switch the collector current on or off. A simple model for the device is presented.

Impact ionization in the base of a hot‐electron AlSb/InAs bipolar transistor

1990 ◽  
Vol 57 (17) ◽  
pp. 1772-1774 ◽  
Author(s):  
Arvind S. Vengurlekar ◽  
Federico Capasso ◽  
T. Heng Chiu
Keyword(s):  
Impact Ionization ◽  
Bipolar Transistor ◽  
Hot Electron

scholarly journals Investigation of the static current gain for InP/InGaAs single heterojunction bipolar transistor

2019 ◽  
Vol 13 (3) ◽  
pp. 1345
Author(s):  
Jihane Ouchrif ◽  
Abdennaceur Baghdad ◽  
Aicha Sshel ◽  
Abdelmajid Badri ◽  
Abdelhakim Ballouk
Keyword(s):  
Heterojunction Bipolar Transistors ◽  
Communication Systems ◽  
Bipolar Transistors ◽  
Bipolar Transistor ◽  
Heterojunction Bipolar Transistor ◽  
Current Gain ◽  
Technological Parameters ◽  
Device Structure ◽  
Optimal Values ◽  
Output Characteristics

<p>Heterojunction Bipolar Transistors are being used increasingly in communication systems due to their electrical performances. They are considered as excellent electronic devices. This paper presents an investigation of the static current gain β based on two technological parameters related to the device geometry for InP/InGaAs Single Heterojunction Bipolar Transistor (SHBT). These parameters are the base width  and the emitter length . We used Silvaco’s TCAD tools to design the device structure, and to extract the static current gain β from I-V output characteristics figures. According to this investigation, we determined the optimal values of the examined parameters which allow obtaining the highest static current gain β.</p>

Quantitative Thickness Measurements of Thin Oxides Using Low Energy Loss Filtered TEM Imaging

2001 ◽  
Vol 7 (S2) ◽  
pp. 560-561
Author(s):  
R. Pantel ◽  
E. Sondergard ◽  
D. Delille ◽  
L.F.Tz. Kwakman
Keyword(s):  
Silicon Oxide ◽  
Bipolar Transistors ◽  
Vlsi Circuits ◽  
Current Gain ◽  
Active Devices ◽  
Bicmos Technology ◽  
High Resolution Tem ◽  
Thin Silicon ◽  
A New Technique ◽  
Hole Current

A technique for very thin silicon oxide measurements using energy filtered TEM (EFTEM) is presented and applied for BiCMOS technology optimization.In advanced VLSI circuits, thin silicon oxide layers are used as critical part of active devices such as MOS or bipolar transistors (BiCMOS). Today the 2 nm thick gate oxides of the 0.12 urn generation MOS transistors can be controlled using high resolution TEM (HRTEM). However, for the next generations these measurements will become difficult or will necessitate Cs corrected microscopes'. For the NPN bipolar transistor very thin oxides (less than 0.5 nm) are used at the base-emitter interface to control the forward base (hole) current and improve the transistor current gain. This interface presents generally some roughness and the oxide control is impossible using HRTEM. in this communication we demonstrate a new technique for very thin oxide measurement using low loss energy filtered TEM (EFTEM).

Device Simulation and Design Optimization for Diamond Based Insulated-gate Bipolar Transistors

2006 ◽  
Vol 956 ◽  
Author(s):  
Haitao Ye ◽  
Niall Tumilty ◽  
David Garner ◽  
Richard B. Jackman
Keyword(s):  
Carrier Concentration ◽  
Potential Distribution ◽  
Device Simulation ◽  
Bipolar Transistors ◽  
Bipolar Transistor ◽  
Current Gain ◽  
Two Dimensional ◽  
Insulated Gate Bipolar Transistors ◽  
Base Region ◽  
Insulated Gate Bipolar Transistor

ABSTRACTA diamond based insulated gate bipolar transistor is incorporated into a two-dimensional device simulator (MEDICI) to examine the current gain (β) and potential distribution across the device. Initially, work has focused on an important component of IGBT structure, the PNP bipolar transistor, which has been simulated and is reported upon in this paper. Empirical parameters for emitter and collector regions were used. Various carrier concentrations for base region were used to optimize the simulation. It was found that decreasing the thickness of base region leads to an increase in current gain. A buffer layer is needed to prevent the punch-through at low carrier concentration in the base region. Various approaches of increasing the current gain are also discussed in this paper.

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.

scholarly journals Degradation of Junction Parameters of an Electrically Stressed NPN Bipolar Transistor

2001 ◽  
Vol 24 (3) ◽  
pp. 155-163 ◽  
Author(s):  
N. Toufik ◽  
F. Pélanchon ◽  
P. Mialhe
Keyword(s):  
Electrical Properties ◽  
Degradation Process ◽  
Bipolar Transistor ◽  
Current Gain ◽  
Hot Carrier ◽  
Electrical Stress ◽  
Hot Carrier Degradation

The effect of an electrical ageing on npn bipolar transistor has been studied. The current gain decreases substantially and the electrical properties are discussed. The emitter-base junction parameters are degraded during the electrical stress experiments. Both the amplitude and the rate of this degradation depend on the stress duration. The evaluation of these parameters allows to discuss hot carrier degradation process, to estimate the stress magnitude and to control the device.

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