Abstract/Details

Development of tunnel diode devices and models for circuit design and characterization


2009 2009

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Abstract (summary)

Historically, the microelectronics industry has scaled down CMOS transistor dimensions in order to increase operating speeds, decrease cost per transistor, and free up on-chip real estate for additional chip functions. There are numerous challenges involved with scaling transistors down to the near term 32 nm node, and beyond. These challenges include short gate lengths, very thin gate oxides, short channel effects, quantum effects, band-to-band tunneling from source to drain, Gate Induced Drain Leakage, Fowler-Nordheim tunneling, and increasing dopant concentrations.

Field effect transistor circuits augmented with tunnel diodes lead to decreased circuit footprints, decreased device count, improved operating speeds, and lower power consumption without the need to solve current CMOS scaling challenges. Recently, N-on-P Si/SiGe resonant interband tunnel diodes (RITD) have been monolithically integrated with CMOS transistors. To further improve the benefits of RITD augmented circuits, P-on-N RITDS and all-Si RITDs were developed. Reported maximum peak-to-valley current ratios (PVCR), a key quantitative parameter of TDs, of 1.32 and 3.02 were measured, respectively.

Since integrated circuits operate at elevated temperatures, the I-V characteristics of various TDs were measured at temperatures ranging from room temperature up to 200°C. Three figures of merit were extracted; (i) peak current density (JP), (ii) valley current density (J V), and (iii) PVCR. Normalizing over their respective values at room temperature allowed for direct comparison between the various TD structures. This method allowed the author to determine that all devices show a similar JP response. However, the Si/SiGe RITD structure was overall least sensitive to temperature variations.

Furthermore, to design and optimize TD augmented circuits, a SPICE compatible model was developed. Past models have discontinuities, kinks in their slopes, difficult parameters to extract, unknown parameters, no closed form solutions, and/or poor fits to measured data. For this work a modified version of the S. M. Sze model with a superior match to experimental data, for Si based Esaki tunnel diodes (ETD) was developed. Using the developed model, several circuits were simulated, which were broken up into two groups. The first group of circuits is comprised of one TD and one of the following; (i) resistor, (ii) NMOS transistor, or (iii) TD. Finally, the behaviors learned from the simple circuits were used to simulate several TD augmented circuits such as (i) ADC comparator, (ii) TSRAM, (iii) and four basic logic gates.

Indexing (details)


Subject
Computer Engineering;
Electrical engineering
Classification
0464: Computer Engineering
0544: Electrical engineering
Identifier / keyword
Applied sciences; SRAM; Silicon; Tunnel diodes
Title
Development of tunnel diode devices and models for circuit design and characterization
Author
Pawlik, David J.
Number of pages
111
Publication year
2009
Degree date
2009
School code
0465
Source
MAI 48/02M, Masters Abstracts International
Place of publication
Ann Arbor
Country of publication
United States
ISBN
9781109508222
Advisor
Rommel, Sean L.
Committee member
Kurinec, Santosh K.; Moon, James E.
University/institution
Rochester Institute of Technology
Department
Microelectronic Engineering
University location
United States -- New York
Degree
M.S.
Source type
Dissertations & Theses
Language
English
Document type
Dissertation/Thesis
Dissertation/thesis number
1470385
ProQuest document ID
305074099
Copyright
Database copyright ProQuest LLC; ProQuest does not claim copyright in the individual underlying works.
Document URL
http://search.proquest.com/docview/305074099
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