Ohmic Contacts to p-Type III-V Semiconductors for the Base of Heterojunction Bipolar Transistors

2019 ◽  
Vol 3 (5) ◽  
pp. 47-56
Author(s):  
Suzanne E. Mohney ◽  
Eric Lysczek ◽  
Sammy Wang ◽  
Joshua Robinson
Keyword(s):  
Heterojunction Bipolar Transistors ◽  
Ohmic Contacts ◽  
Bipolar Transistors ◽  
Type Iii ◽  
P Type

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

p-GaAs Base Regrowth for GaN HBTs and BJTs

2000 ◽  
Vol 622 ◽  
Author(s):  
G. Dang ◽  
A.P. Zhang ◽  
X.A. Cao ◽  
F. Ren ◽  
S.J. Pearton ◽  
...  
Keyword(s):  
Heterojunction Bipolar Transistors ◽  
Inductively Coupled Plasma ◽  
Ohmic Contacts ◽  
Contact Region ◽  
Chemical Vapor ◽  
Bipolar Transistors ◽  
Organic Chemical ◽  
Carbon Doped ◽  
Inductively Coupled ◽  
P Type

ABSTRACTLow resistance ohmic contacts are difficult to form to p-type GaN and AlGaN due to the unavailability of growth methods for highly p-doped GaN and AlGaN. A p-type carbon-doped GaAs regrowth on p-GaN prior to ohmic metallization has been shown in previous work to improve contact resistance to p-GaN [13]. Applying the regrowth method to the p-base regions of npn structured bipolar transistors, AlGaN/GaN heterojunction bipolar transistors and GaN bipolar junction transistors have been demonstrated. GaN/AlGaN epilayers were grown with a molecular beam epitaxy system. Highly carbon-doped p-GaAs (1020 cm−3) was regrown on the devices (∼500 Å) in the base contact region by metal organic chemical vapor deposition after emitter mesa etching. Emitter and base mesa structures were formed by Inductively Coupled Plasma etching under low damage conditions with a Cl2/Ar chemistry. SiO2 was used for emitter sidewall formation to reduce leakage current to the emitter, as well as for a mask for GaAs base regrowth. Very high current densities were obtained for common base operation in both device types. The devices were operable at 250 °C.

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.

Incorporation and Diffusion of P-Type Dopants for Metal Organic Vapor Phase Epitaxy

1988 ◽  
Vol 144 ◽  
Author(s):  
M. A. Tischler ◽  
T. F. Kuech
Keyword(s):  
Heterojunction Bipolar Transistors ◽  
High Performance ◽  
Electrical Characterization ◽  
Bipolar Transistors ◽  
Organic Vapor ◽  
Dopant Profile ◽  
Metal Organic ◽  
Initial Placement ◽  
P Type ◽  
And Diffusion

ABSTRACTThe control of p-type dopants is very important in producing high performance minority carrier devices such as heterojunction bipolar transistors (HBT) and lasers. In this study, an electrical characterization technique is described which is very sensitive to the p-type dopant profile in a heterojunction. Both the placement of the dopant, i.e. the as-grown profile, and thermal diffusion effects have been investigated. The factors which control the initial placement and subsequent diffusion of the dopant species have been determined and used to produce device-quality GaAs/Al0.30Ga0.70As p+/n heterojunctions.

The Challenge of GaAs Heterojunction Bipolar Transistor Integrated Circuit Technology.

1988 ◽  
Vol 144 ◽  
Author(s):  
Han-Tzong Yuan
Keyword(s):  
Integrated Circuits ◽  
Heterojunction Bipolar Transistors ◽  
Integrated Circuit ◽  
Large Scale ◽  
Ohmic Contacts ◽  
Bipolar Transistors ◽  
Bipolar Transistor ◽  
Heterojunction Bipolar Transistor ◽  
The Status ◽  
Impurity Doping

ABSTRACTThe status and progress of AlGaAs/GaAs heterojunction bipolar transistor integrated circuits are reviewed. The challenge of fabricating large-scale integrated circuits using heterojunction bipolar transistors is discussed. Specifically, the issues related to low defect epitaxial materials, localized impurity doping techniques, simple and reliable ohmic contacts, and multilevel interconnects are examined.

Sign in / Sign up

Export Citation Format

Share Document