SNN 519

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SNN 519
TSR-QD Based Memory Devices

• Presenters
• Hai Nguyen
• Sasha Bakhru
• Sumit Kumar

May 07, 2004
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Company Vision Mission

• Vision
• To be the technology leader in the solid state
  memory, serving computing and consumer electronic
  industry.
• Mission
• To develop world-class non-volatile memory
  devices and partner with manufacturers
  distributors to mass produce market the
  products at a competitive price.

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Business strategy

• Develop a framework for RD
• Generate intellectual property
• Introduce new product in pipeline every two (2)
  years
• Current Technology Focus non-volatile memory
  devices using by the Tetrahedral-Shaped Recess
  Quantum Dot technology (TSR-QD)

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Types of Memory

• RAM (Random Access Memory)
• Volatile memory Data can be written, changed
  and deleted
• ROM (Read Only Memory)
• Non-volatile, Data erase cycle limited, entire
  data get erased
• Hybrid Combined features of RAM and ROM
• Non-volatile, unlimited read and write cycle
• Flash memory has best features high density,
  low cost, fast
• in reading, durable, low power usage, low writing
  voltage

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Characteristics of various memory types
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QD- An overview

• Electron confinement in very small dimension
  leads to quantum effect
• types of electron confinement

• Quantum dots artificial atoms having discrete
  energy levels
• QD can have 1 or 0 as the spin of electron can
  be up and down
• Memory is stored as millions of zeros and ones
  on the device

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Why QD for memory devices

• Ultra small size QD so can be operated with
  just a few electrons
• and holes
• Enormously high device integration due to small
  size
• Low chip power consumption
• charge carriers confined in zero dimensional
  space
• Reduced density of states restricts states
  available for electrons
• and holes to tunnel
• Number of electrons in dots can be precisely
  controlled by gate
• voltage

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Framework for RD
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Process for new product development

Product
Discussion
Briefing
/
S
w/ Mfrs.
Market
U
Assessment
M
M
Design
A
Develop
Analysis
R
Manuaf. Process
Y
Apply for
Patent
D
GO
O
Finalize Spec.
C
NO-GO
MOU
Product
U
DECISION BY PARTNERS
Testing
M
E
N
Marketing Analysis
Mfrs. Sign MOU
T
Test Products
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TSR-QD technology evaluation

• Independently change the In-rich InGaAs content
  at the TSR bottom thickness of InGaAs during
  MOCVD growth
• Control the dot position in the lateral direction
• Vertically align QDs and control the height of
  each TSR by stacking TSR-QDs
• Provide a high uniformity of dot size

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TSR-QD fabrication setup

• Substrate GaAs (111)B
• Mask 100 nm thick SiO2
• Etchant 0.5 Br2-ethanol solution

• Method MOCVD
• Sources TMGa, TMIn, AsH3
• Variables flow-rate and T

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TSR-QD devices

• TSR-QD is placed between nonvolatile
  InGaAs/AlGaAs dope-channel heterostructure FET
  and gate electrode
• Device can be programmed by tunneling electrons
  through AlGaAs barrier from the gate

Substrate 75 nm thick Si-doped n-GaAs at 800C
50 Torr
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TSR-QD product advantages

• Ultra high memory density at a ultra small space
• The discrete energy of QD is confined in zero
  dimensional space
• A single quantum dot can functions as a
  microelectronic unit
• Low power consumption at room temperature

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TSR-QD product challenge

• Obtain power gain in molecular circuits
• Arrange trillions of QDs in devices achieving
  molecular electronic interfaces
• Yield two bits in a space of 0.077 square microns
• Develop a low cost process that is suitable for
  rapid processing manufacturing

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TSR-QD product timeline
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Financial analysis for TSR-QD

• Initial Costs Incurred
• 1000 sqft clean space
• Equipment Furnish lab as conventional
  semiconductor research facility
• Big Items
• MOCVD tool
• Laser Lithography tool
• PECVD tool

Total Cost 1,500,000
Annual Cost of Upkeep 5,000 sqft
laboratory space (lease and maintenance of
space) Raw materials

Total Cost 200,000
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Human Resources
Annual Pay Levels PhD
65,000 MBA 60,000 JD
(Part Time) 50,000 MS
50,000 BS 40,000 Total Annual Cost
1,000,000
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Market opportunities

• Potentially replace the existing memory
  technologies ( DRAM, SRAM, Flash, universal
  memories etc.)
• Apply in commercial products (stationary, mobile
  portable, transportation, health care)
• Suitable for military and space applications

(InfoTech Trends database)
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Memory product lifecycle forecast
(InfoTech Trends database)
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Current QD memory pioneers

• Fujitsu Ltd.Poly-Si materials with Poly-Si QD
  material using E-beam/etch method
• Minnesota SOI material with Poly-Si QD material
  using E-beam/etch method
• Fujitsu SOI material with Poly-Si QD material
  using E-beam/etch method
• IBM SOI material with Poly-Si QD material using
  E-beam/etch method
• Sony GaAs material with InAs QD material using
  Epitaxial self assembly method

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Conclusions

• (cost saving)
• (Technology performance)
• (Market time)

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References