Realization of Self-Powered Electronics by 3-D Integration

1
Realization of Self-Powered Electronics by 3-D
Integration
Zeynep Dilli, Neil
Goldsman, Martin Peckerar and George Metze()

Dept. of Electrical and Computer
Engineering, University of Maryland, College
Park, MD 20742 USA ()Laboratory for Physical
Sciences, 8050 Greenmead Drive, College Park,
20740 MD USA
Introduction A micro-sized three-dimensionally
integrated circuit (3DIC) with self-powering and
energy storage units is designed for
fabrication. ?Self-powered sensor units
Challenge for smart dust systems.

• Photodiode Array Design
• For a given incident optical power Pinc ,
  iphRPinc
• R, responsivity R??/1.24.
• ?, quantum efficiency ?(1-R)?(1-exp(-ad))
• (1-R)Surface reflection?non-recombined carrier
  ratio aabsorption coefficient dphotosensitive
  material depth.
• 0.18 um SOI process Si depth is 50 nm only.
• Under daylight 6.6 pA per mm2 net assigned
  design area 250 mm2.
• Two types lateral pin- and annular pn-junctions.

Layout Three tiers connected with dense vertical
vias.
Top tier PD arrays bonding pads Middle
tier 30 pF storage capacitor Bottom tier
Local oscillator, output buffer
System Overview
Lateral PIN Photodiode Junction n-type threshold
adjust implant p-type low doped
body/intrinsic Si. Advantage Large depletion
width. Disadvantage i region not recommended
for use.
Left Only implant layers shown. Right Full
diode layout shown. An array of 52 of these
diodes is in the final layout expected 99.5 pA
per diode.
System Concept Available tiers each meet a
general function in a specific way.
Circuit Operation Photocurrent
charges Cstorage ?Inverter rail voltage. Inverter
switching discharges Cst ? Vrail stabilizes.
Tier Function In this design Also could be
Top Tier Sensors Power-harvesting photodiode arrays Data (sound, light, temperature) sensors
Middle Tier Storage A charge-storage capacitor Data storage elements
Bottom Tier Functional Electronics A local oscillator and output buffer Data processors, converters, communication
Annular PN Photodiode Junction n-type threshold
adjust implant p-type threshold adjust implant.
2062 diodes in final layout 3.63 pA expected
per diode.
Top Full operation. Left Start of
oscillation. Right Full oscillation.
Top Only implant layers shown. Right Full
diode layout shown.
dilli_at_eng.umd.edu