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.

Prevention of InP/InGaAs/InP Double Heterojunction Bipolar Transistors from Current Gain Reduction during Passivation

2004 ◽  
Vol 833 ◽  
Author(s):  
Byoung-Gue Min ◽  
Jong-Min Lee ◽  
Seong-Il Kim ◽  
Chul-Won Ju ◽  
Kyung-Ho Lee
Keyword(s):  
Heterojunction Bipolar Transistors ◽  
Silicon Oxide ◽  
Surface Recombination ◽  
Surface States ◽  
Bipolar Transistors ◽  
Base Layer ◽  
Current Gain ◽  
Device Structure ◽  
Double Heterojunction ◽  
Gain Reduction

ABSTRACTA significant degradation of current gain of InP/InGaAs/InP double heterojunction bipolar transistors was observed after passivation. The amount of degradation depended on the degree of surface exposure of the p-type InGaAs base layer according to the epi-structure and device structure. The deposition conditions such as deposition temperature, kinds of materials (silicon oxide, silicon nitride and aluminum oxide) and film thickness were not major variables to affect the device performance. The gain reduction was prevented by the BOE treatment before the passivation. A possible explanation of this behavior is that unstable non-stoichiometric surface states produced by excess In, Ga, or As after mesa etching are eliminated by BOE treatment and reduce the surface recombination sites.

A Microstructual Analysis of Au/Pd/Ti Ohmic Contacts for GaAs-Based Heterojunction Bipolar Transistors (HJBTs)

1991 ◽  
Vol 240 ◽  
Author(s):  
Bernard M. Henry ◽  
A. E. Staton-Bevan ◽  
V. K. M. Sharma ◽  
M. A. Crouch ◽  
S. S. Gill
Keyword(s):  
Structural Properties ◽  
Heterojunction Bipolar Transistors ◽  
Ohmic Contacts ◽  
Heat Treatments ◽  
Bipolar Transistors ◽  
Contact Resistivity ◽  
Base Region ◽  
Specific Contact ◽  
Specific Contact Resistivity ◽  
Contact Resistivities

ABSTRACTAu/Pd/Ti and Au/Ti/Pd ohmic structures to thin p+-GaAs layers have been investigated for use as contacts to the base region of HJBTs. The Au/Pd/Ti contact system yielded specific contact resistivities at or above 2.8 × 10−5Ω:cm2. Heat treatments up to 8 minutes at 380°C caused only limited interaction between the metallization and the semiconductor. The metal penetrated to a maximum depth of ≃2nm. Specific contact resistivity values less than 10−5Ωcm2 were achieved using the Au/Ti/Pd (400/75/75nm) scheme. The nonalloyed Au/Ti/Pd contact showed the best combination of electrical and structural properties with a contact resistivity value of 9 × 10≃6Ωcm2 and Pd penetration of the GaAs epilayer to a depth of cs30nm.

TEMPERATURE DEPENDENT I-V CHARACTERISTICS OF AlGaN/GaN HBTS AND GaN BJTS

2004 ◽  
Vol 14 (03) ◽  
pp. 819-824 ◽  
Author(s):  
HUILI G. XING ◽  
UMESH K. MISHRA
Keyword(s):  
Heterojunction Bipolar Transistors ◽  
Ohmic Contacts ◽  
Voltage Dependence ◽  
Bipolar Transistors ◽  
Current Gain ◽  
Current Crowding ◽  
Temperature Dependent ◽  
Offset Voltage ◽  
Injection Coefficient ◽  
Device Operation

DC I-V characteristics of AlGaN/GaN heterojunction bipolar transistors (HBTs) and GaN homojunction bipolar transistors (BJTs) are analyzed in the temperature range of 200-450 K. At low current levels, the adverse effects of poor ohmic contacts coupled with paths of high leakage make it difficult to extract intrinsic device operation ["Explanation of anomalous current gain observed in GaN based bipolar transistors", Xing et al. IEEE Elect. Dev. Lett. 24(1) 2003:p.4-6]. At intermediate current levels, owing to enhanced ionization of Mg in the base, the HBTs show an increase in current gain resulting from mitigated current crowding, and the BJTs show a decrease in current gain resulting from reduction of emitter injection coefficient. The offset voltage dependence on temperature is also explained.

In-Based Ohmic Contacts to the Base Layer of GaAs-AlGaAs Heterojunction Bipolar Transistors

1990 ◽  
Vol 181 ◽  
Author(s):  
F. Ren ◽  
S. J. Pearton ◽  
W. S. Hobson ◽  
T. R. Fullowan ◽  
A. B. Emerson ◽  
...  
Keyword(s):  
Contact Resistance ◽  
Heterojunction Bipolar Transistors ◽  
Ohmic Contacts ◽  
Bipolar Transistors ◽  
Base Layer ◽  
Specific Contact Resistance ◽  
Current Transport ◽  
Specific Contact ◽  
P Type

ABSTRACTThe use of AuBe-In/Ag/Au p-ohmic contacts for the base layer of GaAs-AIGaAs heterojunction bipolar transistors (HBTs) is described. Annealing at 420°C for 20 sec produces a contact resistivity of 0.095 Ω mm and a specific contact resistance of l.5 × 10-7 Ω cm2, and the surface morphology of the contact is excellent. The role of the silver is as a diffusion barrier to prevent Au spiking into the base layer which could degrade the HBT performance. The presence of the In layer is highly desirable in order to reduce the contact resistance, probably by forming an InGaAs phase at the metal-GaAs interface. Beryllium acts as the p-type dopant, and the top Au layer is used to lower the contact sheet resistance. Current transport through the structure is dominated by tunneling through the barrier due to field emission in the highly doped base layer at p-type doping levels above ∼1019 cm−3

Current gain increase in AlGaAs/GaAs heterojunction bipolar transistors using AlGaAs layer overgrowth

1994 ◽  
Vol 65 (11) ◽  
pp. 1403-1405 ◽  
Author(s):  
S. R. D. Kalingamudali ◽  
A. C. Wismayer ◽  
R. C. Woods ◽  
J. S. Roberts
Keyword(s):  
Heterojunction Bipolar Transistors ◽  
Bipolar Transistors ◽  
Current Gain ◽  
Algaas Layer

Extremely Low Resistance Ohmic Contacts to n-GaAs for AlGaAs/GaAs Heterojunction Bipolar Transistors

1984 ◽  
Vol 23 (Part 2, No. 8) ◽  
pp. L635-L637 ◽  
Author(s):  
Hiroshi Ito ◽  
Tadao Ishibashi ◽  
Takayuki Sugeta
Keyword(s):  
Heterojunction Bipolar Transistors ◽  
Ohmic Contacts ◽  
Bipolar Transistors ◽  
Low Resistance
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