Download 09-bipIC

Budapest University of Technology and Economics
Department of Electron Devices
Microelectronics, BSc course
Bipolar IC technology: set
of elements
http://www.eet.bme.hu/~poppe/miel/en/09-bipIC.pptx
http://www.eet.bme.hu
Budapest University of Technology and Economics
Department of Electron Devices
The bipolar process
► Steps
20-10-2015
/ masks
Microelectronics BSc course, Element set in bipolar IC-s © András Poppe & Vladimír Székely, BME-EET 2008-2014
2
Budapest University of Technology and Economics
Department of Electron Devices
Structure of bipolar IC transistors
base contact
emitter
base
collector contact
collector
burried layer
n type
island
p-Si
substrate
20-10-2015
Microelectronics BSc course, Element set in bipolar IC-s © András Poppe & Vladimír Székely, BME-EET 2008-2014
3
3
Budapest University of Technology and Economics
Department of Electron Devices
Major process steps
1. n+ burried layer doping (for
collector regions)
M
n+
p
20-10-2015
Microelectronics BSc course, Element set in bipolar IC-s © András Poppe & Vladimír Székely, BME-EET 2008-2014
4
Budapest University of Technology and Economics
Department of Electron Devices
Major process steps
n
2. n epi layer growth for the active
islands
n+
p
20-10-2015
Microelectronics BSc course, Element set in bipolar IC-s © András Poppe & Vladimír Székely, BME-EET 2008-2014
5
Budapest University of Technology and Economics
Department of Electron Devices
Major process steps
n p
3. p type isolation doping (deep
diffusion through the n epi layer)
M
n+
p
20-10-2015
Microelectronics BSc course, Element set in bipolar IC-s © András Poppe & Vladimír Székely, BME-EET 2008-2014
6
Budapest University of Technology and Economics
Department of Electron Devices
Major process steps
n p
p+
4. p+ base diffusion
M
n+
p
20-10-2015
Microelectronics BSc course, Element set in bipolar IC-s © András Poppe & Vladimír Székely, BME-EET 2008-2014
7
Budapest University of Technology and Economics
Department of Electron Devices
Major process steps
n p
p+
5. n+ emitter diffusion (also for
better collector contact)
M
n+
p
20-10-2015
Microelectronics BSc course, Element set in bipolar IC-s © András Poppe & Vladimír Székely, BME-EET 2008-2014
8
Budapest University of Technology and Economics
Department of Electron Devices
Major process steps
n p
p+
6. contact window opening
n+
p
20-10-2015
Microelectronics BSc course, Element set in bipolar IC-s © András Poppe & Vladimír Székely, BME-EET 2008-2014
9
Budapest University of Technology and Economics
Department of Electron Devices
Major process steps
n p
p+
6. contact window opening
M
n+
p
20-10-2015
Microelectronics BSc course, Element set in bipolar IC-s © András Poppe & Vladimír Székely, BME-EET 2008-2014
10
Budapest University of Technology and Economics
Department of Electron Devices
Major process steps
n p
p+
7. metallization pattern
n+
p
20-10-2015
Microelectronics BSc course, Element set in bipolar IC-s © András Poppe & Vladimír Székely, BME-EET 2008-2014
11
Budapest University of Technology and Economics
Department of Electron Devices
Major process steps
n p
p+
7. metallization pattern
M
n+
p
Masks needed for a bipolar
process:
burried layer (n+)
isolation (deep p through n epi)
base (p)
emitter (n+)
contact windows
metallization pattern
The process is optimized for
creating good NPN transistors
20-10-2015
Microelectronics BSc course, Element set in bipolar IC-s © András Poppe & Vladimír Székely, BME-EET 2008-2014
12
Budapest University of Technology and Economics
Department of Electron Devices
Set of components
available in bipolar IC-s
►
Resistor with base diffusion
► Resistor + emitter diffusion
► PNP transistors
► Thin film capacitance
► Layout of an OpAmp
20-10-2015
Microelectronics BSc course, Element set in bipolar IC-s © András Poppe & Vladimír Székely, BME-EET 2008-2014
13
Budapest University of Technology and Economics
Department of Electron Devices
Element set available in bipolar
IC processes
20-10-2015
Microelectronics BSc course, Element set in bipolar IC-s © András Poppe & Vladimír Székely, BME-EET 2008-2014
14
Budapest University of Technology and Economics
Department of Electron Devices
Element set in bipolar IC-s
Detail of a bipolar IC – as seen by a scanning electron microscope
20-10-2015
Microelectronics BSc course, Element set in bipolar IC-s © András Poppe & Vladimír Székely, BME-EET 2008-2014
15
Budapest University of Technology and Economics
Department of Electron Devices
Element set in bipolar IC-s
npn (vertical) transistor
Island (well)
Substrate
Base
20-10-2015
Emitter
Buried
layer
Microelectronics BSc course, Element set in bipolar IC-s © András Poppe & Vladimír Székely, BME-EET 2008-2014
16
Budapest University of Technology and Economics
Department of Electron Devices
Element set in bipolar IC-s
the isolation diffusion
20-10-2015
Microelectronics BSc course, Element set in bipolar IC-s © András Poppe & Vladimír Székely, BME-EET 2008-2014
17
Budapest University of Technology and Economics
Department of Electron Devices
Structure of an npn IC transistor
Island
(well)
Substrate
Base
Emitter
Buried
layer
metal
20-10-2015
Microelectronics BSc course, Element set in bipolar IC-s © András Poppe & Vladimír Székely, BME-EET 2008-2014
18
Budapest University of Technology and Economics
Department of Electron Devices
Element set in bipolar IC-s
npn transistors
Process
optimized for
the npn
(vertical)
transistors
Effective emitter edge at the base contact side (I=2 A/cm),
EB br.down: 5-6 V, CB br.down 40-50 V, fT=800-900 MHz
20-10-2015
Microelectronics BSc course, Element set in bipolar IC-s © András Poppe & Vladimír Székely, BME-EET 2008-2014
19
Budapest University of Technology and Economics
Department of Electron Devices
Element set in bipolar IC-s
High current npn transistors
20-10-2015
Microelectronics BSc course, Element set in bipolar IC-s © András Poppe & Vladimír Székely, BME-EET 2008-2014
20
Budapest University of Technology and Economics
Department of Electron Devices
Element set in bipolar IC-s
Different npn transistors
Area efficient solutions:
two transistors in a common isolation well,
multi-emitter transistor
20-10-2015
Microelectronics BSc course, Element set in bipolar IC-s © András Poppe & Vladimír Székely, BME-EET 2008-2014
21
Budapest University of Technology and Economics
Department of Electron Devices
Element set in bipolar IC-s
Different npn transistors
Effective emitter edge at the base contact side (I=2 A/cm)
20-10-2015
Microelectronics BSc course, Element set in bipolar IC-s © András Poppe & Vladimír Székely, BME-EET 2008-2014
22
Budapest University of Technology and Economics
Department of Electron Devices
Element set in bipolar IC-s
Resistor with base diffusion
D  dx
D B
G  
 q   p N B ( x)dx
L
L 0
0
dB
R
island
(well)
d
1
dB
q   p N ( x)dx
0
L
RR
D
20-10-2015
Microelectronics BSc course, Element set in bipolar IC-s © András Poppe & Vladimír Székely, BME-EET 2008-2014
23
Budapest University of Technology and Economics
Department of Electron Devices
Element set in bipolar IC-s
Resistor with base diffusion
There could be multiple resistors in the
same isolation well
20-10-2015
The well must be connected to +UCC!
Microelectronics BSc course, Element set in bipolar IC-s © András Poppe & Vladimír Székely, BME-EET 2008-2014
24
Budapest University of Technology and Economics
Department of Electron Devices
Element set in bipolar IC-s
Resistor with base
diffusion, folded as
a meander
R  100  150
R  100  10 K
R
 0.1% / C
T
Accuracy,
parasistics
20-10-2015
Microelectronics BSc course, Element set in bipolar IC-s © András Poppe & Vladimír Székely, BME-EET 2008-2014
25
Budapest University of Technology and Economics
Department of Electron Devices
How to make components VERY
MUCH identical?
• same layout shape
• same position/orientation
• close to eachother
• larger than minimal size
• same temperature
20-10-2015
Microelectronics BSc course, Element set in bipolar IC-s © András Poppe & Vladimír Székely, BME-EET 2008-2014
26
Budapest University of Technology and Economics
Department of Electron Devices
Element set in bipolar IC-s
Resistor with base diffusion, cross section
reduced by emitter diffusion
R
1
dB
q   p N ( x)dx
dE
20-10-2015
Microelectronics BSc course, Element set in bipolar IC-s © András Poppe & Vladimír Székely, BME-EET 2008-2014
27
Budapest University of Technology and Economics
Department of Electron Devices
Element set in bipolar IC-s
Resistor with base diffusion, cross section
reduced by emitter diffusion
value: few times 100 k
emitter diffusion
base diffusion
Slightly nonlinear
Limited voltage range
R
1
dB
q   p N ( x)dx
dE
20-10-2015
Microelectronics BSc course, Element set in bipolar IC-s © András Poppe & Vladimír Székely, BME-EET 2008-2014
28
Budapest University of Technology and Economics
Department of Electron Devices
Element set in bipolar IC-s
small emitter diffusion resistor
(connection underpass), value
cca. 2 
Emitter
diffusion
Metallization
20-10-2015
Microelectronics BSc course, Element set in bipolar IC-s © András Poppe & Vladimír Székely, BME-EET 2008-2014
29
Budapest University of Technology and Economics
Department of Electron Devices
Element set in bipolar IC-s
Lateral pnp transistor
20-10-2015
Microelectronics BSc course, Element set in bipolar IC-s © András Poppe & Vladimír Székely, BME-EET 2008-2014
30
Budapest University of Technology and Economics
Department of Electron Devices
Element set in bipolar IC-s
Lateral pnp transistor
Multiple transistors
in common well
20-10-2015
Microelectronics BSc course, Element set in bipolar IC-s © András Poppe & Vladimír Székely, BME-EET 2008-2014
31
Budapest University of Technology and Economics
Department of Electron Devices
Element set in bipolar IC-s
Lateral pnp "sector" transistors
overlapping contact window
Forms a current mirror
20-10-2015
Microelectronics BSc course, Element set in bipolar IC-s © András Poppe & Vladimír Székely, BME-EET 2008-2014
32
Budapest University of Technology and Economics
Department of Electron Devices
Element set in bipolar IC-s
Lateral pnp "sector" transistors
I
20-10-2015
I
Also with
circular
shape!
I
3I
Microelectronics BSc course, Element set in bipolar IC-s © András Poppe & Vladimír Székely, BME-EET 2008-2014
33
Budapest University of Technology and Economics
Department of Electron Devices
Element set in bipolar IC-s
Vertical pnp transistor
vertical pnp
structure
n+ no
buried
layer
push and
pull
20-10-2015
amplifier (B)
Microelectronics BSc course, Element set in bipolar IC-s © András Poppe & Vladimír Székely, BME-EET 2008-2014
34
Budapest University of Technology and Economics
Department of Electron Devices
Element set in bipolar IC-s
The thin film capacitor
Metal
dox: 0,1 m (50 V)
Cspec: 3-400pF/mm2
20-10-2015
6
A
10
C   0 r  8,86 1012  3,9  7  345 1012 F
d
10
Microelectronics BSc course, Element set in bipolar IC-s © András Poppe & Vladimír Székely, BME-EET 2008-2014
35
Budapest University of Technology and Economics
Department of Electron Devices
Element set in bipolar IC-s
Thin film (metal-SiO2-n+) capacitor in an OpAmp
Value: cca. 30pF
Cspec: 3-400pF/mm2
20-10-2015
Microelectronics BSc course, Element set in bipolar IC-s © András Poppe & Vladimír Székely, BME-EET 2008-2014
36
Budapest University of Technology and Economics
Department of Electron Devices
Element set in bipolar IC-s
Thin film (metal-SiO2-n+) capacitor in an OpAmp
Compare the size of the capacitor and the transistors!
20-10-2015
Microelectronics BSc course, Element set in bipolar IC-s © András Poppe & Vladimír Székely, BME-EET 2008-2014
37
Budapest University of Technology and Economics
Department of Electron Devices
Element set in bipolar IC-s
The pn junction as a capacitor
The space charge capacitance can be
utilized, but
• voltage dependent (non-linear)
• may not be forward biased!
20-10-2015
EB: 1000pF/mm2
(up to 5 V)
CB: 150pF/mm2
(up to ~50 V)
Microelectronics BSc course, Element set in bipolar IC-s © András Poppe & Vladimír Székely, BME-EET 2008-2014
38
Budapest University of Technology and Economics
Department of Electron Devices
OpAmp
layout,
component arrangement
Symmetry – to assure
same thermal feedback
path.
This layout is not yet the
best.
20-10-2015
T1, T2: NPN, input differential
pair
T3, T4: PNP, lateral
T5, T6, T7: NPN
T10, T11, T13: PNP
lateral transistors
D1, D2: diodes
T16-17: NPN darlington
T19-21: 3 NPN transistors in a
common well
R1, R6: large resistors
R7: base+emitter diff. resistor
R8, R9: small resistors
T22: PNP vertical
T23: NPN vertical
(high current)
Microelectronics BSc course, Element set in bipolar IC-s © András Poppe & Vladimír Székely, BME-EET 2008-2014
39
Budapest University of Technology and Economics
Department of Electron Devices
Thermal effects in analog
IC-s: a bipolar OpAmp
►
►
►
►
20-10-2015
Thermal impedances
Thermal feedback in case of an OpAmp
How does the layout influence the thermal feedback
Layout – thermally optimized
Microelectronics BSc course, Element set in bipolar IC-s © András Poppe & Vladimír Székely, BME-EET 2008-2014
40
Budapest University of Technology and Economics
Department of Electron Devices
The thermal impedances
The transfer impedance
The self impedance
T1 temperature rise
T1
Rth 
[K / W ]
P1
T1 ( )
Z th ( ) 
P( )1
Z th12 ( ) 
T2 ( )
P1 ( )
Zth complex valued
20-10-2015
Microelectronics BSc course, Element set in bipolar IC-s © András Poppe & Vladimír Székely, BME-EET 2008-2014
41
Budapest University of Technology and Economics
Department of Electron Devices
Thermal feedback – in an OpAmp
Stationary state,
VOUT > 0


PT 14  VCC
 VOUT
VR
OUT
L
T  Z141  Z142 PT 14
Vequ   ( Z141  Z142 )V

CC
VOUT
 VOUT 
RL
  -2 mV/oC
20-10-2015
Microelectronics BSc course, Element set in bipolar IC-s © András Poppe & Vladimír Székely, BME-EET 2008-2014
42
Budapest University of Technology and Economics
Department of Electron Devices
Thermal feedback – in an OpAmp
Stationary state
Effect on the open
loop characteristic
20-10-2015
Microelectronics BSc course, Element set in bipolar IC-s © András Poppe & Vladimír Székely, BME-EET 2008-2014
43
Budapest University of Technology and Economics
Department of Electron Devices
Thermal feedback – in an OpAmp
Methods for analysis
Both measurements and simulations were done.
A well known, commercially available circuit was studied
(A741 OpAmp).
Both stationary state and dynamic behaviour.
Identical type from different IC venors: different layout
designs realizing the same electrical schematic.
Actual layout (component arrangement) was identified by
"reverse engineering".
20-10-2015
Microelectronics BSc course, Element set in bipolar IC-s © András Poppe & Vladimír Székely, BME-EET 2008-2014
44
Budapest University of Technology and Economics
Department of Electron Devices
Details of the model
Device under test: A741 OpAmp
Physical layer
structure
Schematic of the
OpAmp
Yellow transistors considered by electro-thermal model
20-10-2015
Microelectronics BSc course, Element set in bipolar IC-s © András Poppe & Vladimír Székely, BME-EET 2008-2014
45
Budapest University of Technology and Economics
Department of Electron Devices
Reverse engineered layouts
Layout "A"
20-10-2015
Microelectronics BSc course, Element set in bipolar IC-s © András Poppe & Vladimír Székely, BME-EET 2008-2014
46
Budapest University of Technology and Economics
Department of Electron Devices
Reverse engineered layouts
Layout "B"
20-10-2015
Microelectronics BSc course, Element set in bipolar IC-s © András Poppe & Vladimír Székely, BME-EET 2008-2014
47
Budapest University of Technology and Economics
Department of Electron Devices
Open loop characteristics
(measurement and simulation)
Layout "A"
20-10-2015
Microelectronics BSc course, Element set in bipolar IC-s © András Poppe & Vladimír Székely, BME-EET 2008-2014
48
Budapest University of Technology and Economics
Department of Electron Devices
Open loop characteristics
(measurement and simulation)
Layout "B"
20-10-2015
Microelectronics BSc course, Element set in bipolar IC-s © András Poppe & Vladimír Székely, BME-EET 2008-2014
49
Budapest University of Technology and Economics
Department of Electron Devices
Frequency domain analysis
Thermal effects in the output impedance
Z OUT (ω) 
20-10-2015
Re
Gv (ω)


(VCC
 VOUT )γ( Z141  Z142 )
1  βGv (ω) 1  βGv (ω)
Microelectronics BSc course, Element set in bipolar IC-s © András Poppe & Vladimír Székely, BME-EET 2008-2014
50
Budapest University of Technology and Economics
Department of Electron Devices
Frequency domain analysis
Layout "A", upper transistor on, G=104
Effect appears even if there
is no load!
20-10-2015
Microelectronics BSc course, Element set in bipolar IC-s © András Poppe & Vladimír Székely, BME-EET 2008-2014
51
Budapest University of Technology and Economics
Department of Electron Devices
Frequency domain analysis
"A"
"B"
Difference only in layout!
20-10-2015
Microelectronics BSc course, Element set in bipolar IC-s © András Poppe & Vladimír Székely, BME-EET 2008-2014
52
Budapest University of Technology and Economics
Department of Electron Devices
The ideal layout
"A"
"B"
Input differential
pair
Output transistors
(common centroid)
20-10-2015
Microelectronics BSc course, Element set in bipolar IC-s © András Poppe & Vladimír Székely, BME-EET 2008-2014
53