A Low Temperature Technology on the Base of
Hydrogen Enhanced Thermal Donor Formation
for Future High-Voltage Applications
R. Job 1, A.G. Ulyashin 1, W.R. Fahrner 1,
1
University of Hagen, Dept. of Electrical Engineering and Information
Technology (LGBE), Germany
F.J. Niedernostheide 2, H.J. Schulze 2,
2 Infineon AG, Munich, Germany
E. Simoen 3, C.L. Claeys 3, 4,
3 IMEC, Leuven, Belgium
4 University of Leuven (KU), Dept. of Electrical Engineering, Belgium
G. Tonelli 5
5 INFN, Pisa, Italy
Outline of the Talk
• Introduction
• Experimental
(substrates, H-plasma treatments & annealing)
• Experimental Results
(analysis by SRP measurements, I-V and C-V curves, DLTS,
Raman spectroscopy, SEM, TEM )
• Discussion
(low temperature doping by thermal donors
 low thermal budget technology for special devices,
i.e. high-voltage devices, radiation detectors, etc.)
• Summary
Dr. Reinhart Job, University of
Hagen, Germany
Thermal Donors (TDs)
• 'Old thermal donors' (TDs), oxygen related double donors
(TDDs)
– formation at T  300 - 500 °C
– T > 550 °C  TDs are dissolved
– family of 'bistable' double donors TDD1, TDD2, ... , TDD16, ... (?)
– classification by IR-absorption spectroscopy
– 2 energy levels of the donor: 70 meV, 150 meV
– formation rate R correlated with [Oi] and [Cs]:
[Oi] high  R high, [Cs] high  R low
• Our investigations:
 'Old thermal donors' (i.e. TDDs)
• Other types of TDs:
NDs, NTDs, STDs
Dr. Reinhart Job, University of
Hagen, Germany
Thermal Donors
• 'New donors' (NDs)
– formation at T  550 - 800 °C
– R correlated with [Oi] and [Cs]:
[Oi] high  R high, [Cs] high  R high
– energy level of the donor: 17 meV
• 'New thermal donors' (NTDs)
–
–
–
–
formation at T  300 - 500 °C
NTDs appear only after very long annealing times (> 105 min)
NTDs  double donors
large agglomerates of oxygen (?)
• 'Shallow thermal donors' (STDs)
– formation at T  300 - 500 °C (low concentrations)
– family of 7 single donors
Dr. Reinhart Job, University of
Hagen, Germany
Low Thermal Budget Doping by Thermal Donors
• Hydrogen enhances thermal donor (TD) formation in
Cz silicon
• Thermal donors: 'old' TDs, i.e. TDDs (oxygen related
double donors)
• Counter doping of initial p-type Cz Si by hydrogen
enhanced TD formation
 formation of deep p-n junctions
• Developed process routes:
- "1-step-process"
- "2-step-process"
Dr. Reinhart Job, University of
Hagen, Germany
Experimental
• Substrates:
– p-type Cz Silicon wafers
( = 3 inches, d  370 - 380 µm, (100)-oriented)
Impurities:
[Oi]  7 - 81017 cm-3
(specified, IR-Absorption)
[Cs] < 51016 cm-3
(specified)
Doping:
 = 12 - 20 cm,  = 5 - 10 cm,  = 1 - 2 cm
[B]  61014 cm-3 - 1.31016 cm-3
Dr. Reinhart Job, University of
Hagen, Germany
Experimental
Applied measurements:
“Spreading-Resistance-Probe”- (SRP-) measurements
- resistance profiles in dependence on the depth
- estimation of the location of p-n junctions
Thermoelectrical Microprobe Method (‘Seebeck-Effect’)
- determination of the type of doping (n-type / p-type)
C(V) measurements
- characterization of p-n junctions due to TD formation
Infrared- (IR-) absorption measurements
- characterization of TD types (”TDDi- family")
I(V) measurements
- characterization of diodes (”TD-Diodes”)
Dr. Reinhart Job, University of
Hagen, Germany
"1-Step-Process" for TD Formation
• Hydrogen enhanced TD formation in Cz Si only
by H-plasma treatment
• "1-step-process":
TDD formation during H-plasma treatment
(Tplasma = 400 - 450 °C, tplasma  30 min)
• Cz Si wafers: [B] = 11015 cm-3, [Oi] = 7 - 81017 cm-3
• Example: DC plasma treatment
(RIE setup, 500 V plate voltage, 440 µA/cm2)
 formation of TDDs, [TDD]  11016 cm-3
 formation of deep p-n junctions (counter doping)
Dr. Reinhart Job, University of
Hagen, Germany
Formation of p-n Junctions ("1-Step-Process")
SRP measurements:
10
6
30 min DC H-Plasma
 p-n junction
T pl = 400 °C
Substrate:
12 cm Cz Si,
[B] = 11015 cm-3
(p-type)
H-Plasma:
30 min at 400 °C
(1-step-process)
SR (  )
location
10
5
10
4
p-n junction
p-type
n-type
10
3
0
100
200
300
Depth (µm)
Dr. Reinhart Job, University of
Hagen, Germany
400
500
Formation of p-n Junctions ("1-Step-Process")
Free carrier concentration Nc in dependence on the depth
10
16
n-type
p-type
NA
-3
[N c] (cm )
p-n junction
Substrate:
12 cm Cz Si,
[B] = 11015 cm-3
(p-type)
H-Plasma:
30 min at 400 °C
(1-step-process)
10
15
30 min DC H-Plasma
10
T pl = 400 °C
14
0
100
200
300
400
Depth (µm)
Dr. Reinhart Job, University of
Hagen, Germany
500
600
Formation of p-n Junctions ("1-Step-Process")
Electron concentration Ne(TD) due to
TDDs in dependence
on the depth
10
16
p-type
-3
N e(TD) (cm )
p-n junction
Substrate:
12 cm Cz Si,
[B] = 11015 cm-3
(p-type)
H-Plasma:
30 min at 400 °C
(1-step-process)
10
NA
15
n-type
10
14
0
100
200
300
Tiefe (µm)
Dr. Reinhart Job, University of
Hagen, Germany
400
500
5x10
-6
C-3  Vbias
 linear graded
junction
4x10
-6
-6
-3
3x10
2x10
-6
1x10
-6
Substrate:
12 cm Cz Si,
[B] = 11015 cm-3
(p-type)
H-Plasma:
30 min at 400 °C
(1-step-process)
C (pF )
C(V) measurements:
-3
Formation of p-n Junctions ("1-Step-Process")
0
0
-5
-10
Dr. Reinhart Job, University of
Hagen, Germany
-15
-20
V BIAS (V)
-25
-30
Formation of p-n Junctions ("1-Step-Process")
SRP measurements:
 p-n junction
10
6
45 min DC H-Plasma / T pl = 400 °C
Substrate:
12 cm Cz Si,
[B] = 11015 cm-3
(p-type)
H-Plasma:
45 min at 400 °C
(1-step-process)
SR (  )
location
10
5
10
4
p-n junction
n-type
10
p-type
3
0
100
200
300
Depth (µm)
Dr. Reinhart Job, University of
Hagen, Germany
400
500
Formation of p-n Junctions ("1-Step-Process")
10
16
n-type
p-type
pn-junction
-3
[N c] (cm )
Free carrier concentration Nc in dependence on the depth
Substrate:
12 cm Cz Si,
[B] = 11015 cm-3
(p-type)
H-Plasma:
45 min at 400 °C
(1-step-process)
10
15
10
14
45 min DC H-Plasma / T pl = 400 °C
0
100
200
300
Depth (µm)
Dr. Reinhart Job, University of
Hagen, Germany
400
500
Formation of p-n Junctions ("1-Step-Process")
SRP measurements:
SR (  )
p-n junction depth in
dependence on the
initial p-type doping
Substrate:
1, 12 cm Cz Si,
[B]  1015, 1016 cm-3
(p-type)
H-Plasma:
120 min at 400 °C
(1-step-process)
10
7
120 min DC H-Plasma / T pl = 400 °C
10
6
10
5
10
4
10
3
12  cm
1  cm
0
100
200
300
Depth (µm)
Dr. Reinhart Job, University of
Hagen, Germany
400
500
Formation of p-n Junctions ("1-Step-Process")
SRP measurements:
10
Substrate:
12 cm Cz Si,
[B] = 11015 cm-3
(p-type)
H-Plasma:
120 min at 400 °C
(1-step-process)
SR (  )
p-n junction depth in
dependence on the
amount of incorporated hydrogen
8
120 min DC H-Plasma / T pl = 400 °C
10
7
10
6
10
5
10
4
10
3
60 µA cm
0
100
-2
440 µA cm
200
300
Depth (µm)
Dr. Reinhart Job, University of
Hagen, Germany
400
-2
500
Formation of p-n Junctions ("1-Step-Process")
Substrate:
12 cm Cz Si,
[B] = 11015 cm-3
(p-type)
H-Plasma:
at 400 °C
(1-step-process)
-3
Ne(TD) in dependence on the hydrogen
dose
N e(TD) (cm )
C(V) measurements:
2x10
16
2x10
16
1x10
16
5x10
15
0
0
5x10
18
19
1x10
2x10
-2
H-dose (cm )
Dr. Reinhart Job, University of
Hagen, Germany
19
2x10
19
Formation of p-n Junctions ("1-Step-Process")
SRP measurements:
10
p-n junction depth in
dependence on the
plasma treatment
time
30 min
SR (  )
Substrate:
12 cm Cz Si,
[B] = 11015 cm-3
(p-type)
7
H-Plasma:
30 - 120 min at 400 °C
(1-step-process)
10
6
10
5
10
4
10
3
120 min
45 min
DC H-Plasma / T pl = 400 °C
0
100
200
300
Depth (µm)
Dr. Reinhart Job, University of
Hagen, Germany
400
500
Kinetic Analysis of the "1-Step-Process"
Time dependences of H and H2 concentrations:
[ H ]
 [H ]
2
 DH 
 2  K1  [ H ]  K 2  [ H 2 ]
2
t
x
[ H 2 ]
 K1  [ H ] 2  K 2  [ H 2 ]
t
2
DH: diffusion constant of atomic hydrogen
K1 : rate of H2 formation
K2 : dissociation constant of H2 molecules
Dr. Reinhart Job, University of
Hagen, Germany
Kinetic Analysis of the "1-Step-Process"
 Eb 
K 1  8  R0  DH ,
K 2    exp  

 kT 
 0.48 
3
DH  9.67  10  exp  

 kT 
K1 : rate of H2 formation
K2 : dissociation constant of H2 molecules
DH: "Van Wieringen-Warmholtz" relation  diffusion constant
R0 : capture radius (R0 = 5 Å *))
 : vibration frequency of the dissociation of H2
Eb: binding energy (Eb = 1.6 eV)
*) J.T. Borenstein et al., J. Appl. Phys. 73, 2751 (1993)
Dr. Reinhart Job, University of
Hagen, Germany
Kinetic Analysis of the "1-Step-Process"
Time dependence of [TD] :
 [ NTD ]
 K3  [ H ]
t
NTD: concentration of thermal double donors ("TDD")
 compensation (p-n junction): 2 [NTD] = [B]
K3 : free parameter (deduced by fitting of experimental data)
K3 = 3.810-2 s-2
Boundary condition:
x = 0, t  0:
[H0], with [H0] = 1014 cm-3
(constant hydrogen concentration at the wafer surface)
Dr. Reinhart Job, University of
Hagen, Germany
Formation of p-n Junctions ("1-Step-Process")
10
16
[TDD], [H], [H2] in
dependence on the
depth
10
15
10
14
10
13
10
12
[TDD]
-3
[H], [H 2 ], [TD] (cm )
Simulated curves:
Assumption:
T = 400 °C
t = 30 min
(1-step-process)
[TDD]-profile:
K3 = 3.810-2 s-2
(Fit to exp. Data)
[H]
10
11
10
10
[H 2 ]
0
100
200
300
Depth (µm)
Dr. Reinhart Job, University of
Hagen, Germany
400
500
Formation of p-n Junctions ("1-Step-Process")
Comparison of
simulated [TD]
profiles &
experimental data
10
17
10
16
10
15
10
14
-3
[TD] (cm )
p-n junctions (exp.)
Assumption:
T = 400 °C
t = 30, 45, 120 min
(1-step-process)
10
Fit to exp. Data:
 K3 = 3.810-2 s-2
t plasma = 120 min
t plasma = 45 min
t plasm a = 30 m in
13
0
100
200
300
Depth (µm)
Dr. Reinhart Job, University of
Hagen, Germany
400
500
Kinetic Analysis of the "1-Step-Process"
Summary / Conclusions:
• "1-Step-Process":  various processes occur
– T > 200 °C  no acceptor passivation
– incorporation of hydrogen from the plasma ambient
– formation and decay of H2 complexes
– diffusion of H via interstitial lattice sites
– H lowers the barrier for the diffusion of Oi
– probability is enhanced that Oi forms a TD complex
 hydrogen supports the TD formation
– loss of Oi due to the incorporation of Oi into TD-complexes
Question:
Charge state of hydrogen (H0, H+, H-) ?
Dr. Reinhart Job, University of
Hagen, Germany
"2-Step-Process" for TD Formation
• Hydrogen enhanced TD formation in Cz Si by H-plasma
treatment and subsequent annealing
• "2-step-process":
TDD formation during post-hydrogenation annealing
- H-plasma exposure: Tplasma  250 °C, tplasma = 60 min
- annealing: Tanneal  450 °C, tanneal  15 min
• Cz Si wafers: [B] = 11015 cm-3, [Oi] = 7 - 81017 cm-3
• Example: PECVD plasma treatment
(110 Mhz, 50 W, 440 µA/cm2)
 formation TDDs / p-n junctions, [TDD]  11016 cm-3
Dr. Reinhart Job, University of
Hagen, Germany
Formation of p-n Junctions ("2-Step-Process")
SRP measurements:
Substrate:
1.8 - 2.6 cm Cz Si,
[B]  71015 cm-3
(p-type)
H-Plasma:
60 min at 250 °C
Annealing:
at 450 °C/air
SR (  )
p-n junction depth in
dependence on the
post-hydrogenation
annealing time
10
6
10
5
10
4
20' 30'
10'
45' 60'
120'
240'
480'
15' wafer thickness: 367 + 5 µm
 = 1.8 - 2.6  cm
10
3
0
100
200
Depth (µm)
Dr. Reinhart Job, University of
Hagen, Germany
300
400
Formation of p-n Junctions ("2-Step-Process")
SRP measurements:
Substrate:
5 - 10 cm Cz Si,
[B]  21015 cm-3
(p-type)
H-Plasma:
60 min at 250 °C
Annealing:
at 450 °C/air
SR (  )
p-n junction depth in
dependence on the
post-hydrogenation
annealing time
10
6
10
5
10
4
10'
15'
20'
30'
45'
wafer thickness: 378 + 5 µm
60' 120'
240'
480'
 = 5 - 10  cm
10
3
0
100
200
Depth (µm)
Dr. Reinhart Job, University of
Hagen, Germany
300
400
Kinetic Analysis of the "2-Step-Process"
• "2-step-process": 60 min RF H-plasma at  250 °C
+ annealing at 450 °C/air
• Hydrogen supports the formation of TDs, i.e. TDDs
• Supposition:
TD formation / depth of p-n junctions
 penetration of n-type regions into the
wafer bulk are driven by H diffusion
• "Fick's Diffusion Law":
[ H ]
 ( D   )[ H ]
t
[H]: hydrogen concentration, D: diffusion constant, t: time,
Dr. Reinhart Job, University of
Hagen, Germany
Kinetic Analysis of the "2-Step-Process"
[ H ]
 ( D   )[ H ]
t
• "Fick's Law":
• if D = const. 
 d 
[ H ]  [ H 0 ]  erfc 

 4D  t 
(D: diffusion constant, d: depth, t: time, [H0]: surface concentration)
• mean diffusion length:
L  4D t
• assume:
p-n junction depth dpn proportional to diffusion length L:
 dpn  L, i.e. dpn  t1/2
Dr. Reinhart Job, University of
Hagen, Germany
Formation of p-n Junctions ("2-Step-Process")
p-n junction depth:
400
 description by the
"Fick's diffusion law"
L  4D t
(D: diffusion constant)
linear slope 
D = 2.9 10-7 cm2s-1
(5 - 10 cm Cz Si)
D = 7.9 10-7 cm2s-1
Depth (µm)
300
200
100
 = 5 - 10  cm
 = 1.8 - 2.6  cm
0
0
50
(1.8 - 2.6 cm Cz Si)
Dr. Reinhart Job, University of
Hagen, Germany
100
1/2
1/2
t (s )
150
200
Kinetic Analysis of the "2-Step-Process"
• Relation of Van Wieringen and Warmholtz (VWW):
 Ea 

DH  9.67  exp 
 kT 
(Ea = 0.48 eV)
• VWW equation holds for atomic hydrogen !
• extrapolation to 450 °C: DVWW = 4.36 10-6 cm2/s
• experiment:
D  7.9 10-7 cm2s-1 (1  cm Cz Si)
D  2.9 10-6 cm2s-1 (5  cm Cz Si)
Dr. Reinhart Job, University of
Hagen, Germany
Formation of p-n Junctions ("2-Step-Process")
RF H-plasma exposure
at room temperature:
7
10
 p-n junction
8h 15'
Substrate:
12 - 20 cm Cz Si,
[B]  1.11015 cm-3
(p-type)
8h 30'
6
10
8h
SR(Ohm)
formation only after
long time annealing at
450 °C (t > 8 hours)
5
10
p-n junction
p-n junction
4
H-Plasma:
60 min at RT
Annealing:
at 450 °C/air
10
0
50
10015020025030
Depth (microns
Dr. Reinhart Job, University of
Hagen, Germany
Kinetic Analysis of the "2-Step-Process"
Summary / Conclusions (1):
• Hydrogen is amphoteric
(standard model: H+ in p-type Si, H0 and H- in n-type Si)
• Estimated diffusion constants  neutral atomic
hydrogen H0 plays the major role for the TD formation
• H0 is responsible for the enhancement of the TD
formation in p-type and n-type Cz Si
• D(H0) is several orders of magnitude larger than the
diffusion constant D(H+) of positively charged H+ ions
 D(H0)/D(H+)  105 *)
*) D. Matthiot, Phys. Rev. B 40, 5867 (1989)
Dr. Reinhart Job, University of
Hagen, Germany
Kinetic Analysis of the "2-Step-Process"
Summary / Conclusions (2):
• "2-Step-Process":  various processes occur
– T > 200 °C  no acceptor passivation occurs
– T  250 °C  immobile hydrogen complexes are created
– T  400 - 450 °C  immobile hydrogen complexes are dissolved
 high concentration of mobile H0
– diffusion of H0 via interstitial lattice sites
– H0 lowers the barrier for the migration of Oi
– probability is enhanced that Oi forms a TD complex
 hydrogen supports the TD formation
Dr. Reinhart Job, University of
Hagen, Germany
Kinetic Analysis of the "2-Step-Process"
Summary / Conclusions (3):
• Dominant reaction at T 250 °C (H-plasma treatment):
H+ + H0  H2 + h+ *)
(H+, H0: hydrogen in positive, neutral state,
h+: hole, compensated by crystal field)
*) S.M. Myers et al., Rev. Mod. Phys. 64, 559 (1992)
•  immobile H2 species: "zero spin clusters (ZSC)"
• Dominant reaction at T 450 °C (annealing):
 decay of ZSCs  large concentration of H0
• "2-step-process"  indirect way for H0 incorporation
"1-step-process"  direct way for H0 incorporation
Dr. Reinhart Job, University of
Hagen, Germany
Formation of Extremely Deep p-n Junctions
SRP measurements:
10
ultra-deep p-n junction in highly oxidized Cz Si
Substrate:
12 cm Cz Si,
[B]  11015 cm-3
(p-type)
H-Plasma:
60 min at 450 °C
µ-wave H-plasma
(1-step-process)
> 1.2 mm (!)
10
SR (  cm)
[Oi] = 1.151018 cm-3
7
6
n-type
10
5
10
4
10
3
p-type
p-n junction
0
500
Dr. Reinhart Job, University of
Hagen, Germany
1000
Depth (µm)
1500
2000
Formation of Extremely Deep Graded Doping
SRP measurements:
10
ultra-deep graded
doping in highly
oxidized Cz Si
Substrate:
5 cm Cz Si,
[P]  11015 cm-3
(n-type)
H-Plasma:
60 min at 450 °C
µ-wave H-plasma
(1-step-process)
n-type Cz Si (5  cm)
SR (  cm)
[Oi] = 1.21018 cm-3
5
10
10
4
H from the
H from the
frontside
backside
3
0
500
Dr. Reinhart Job, University of
Hagen, Germany
1000
Depth (µm)
1500
2000
verification of TDDs
(neutral species up to
the 5th generation)
Substrate:
12 cm Cz Si,
[B]  11015 cm-3
(p-type)
[Oi] = 1.151018 cm-3
H-Plasma:
60 min at 450 °C
µ-wave H-plasma
(1-step-process)
-1
IR-absorption
measurements:
Absorption Coefficient (cm )
Hydrogen Enhanced Thermal Donor Formation
4,5
4,0
p-type
: TDD i (i = 1 - 5)
Cz Si
Oi
3,5
3,0
2,5
2,0
1,5
400
425
450
475
500
525
-1
W avenumber (cm )
Dr. Reinhart Job, University of
Hagen, Germany
550
3,5
-1
IR-absorption
measurements:
Absorption Coefficient (cm )
Hydrogen Enhanced Thermal Donor Formation
verification of TDD+s
(singly ionized species up to the 5th
generation)
Substrate:
12 cm Cz Si,
[B]  11015 cm-3
(p-type)
[Oi] = 1.151018 cm-3
H-Plasma:
60 min at 450 °C
µ-wave H-plasma
(1-step-process)
+
3,0
2,5
: TDD i (i = 1 - 5)
p-Typ
?
Cz Si
2,0
Oi
1,5
1,0
0,5
0,0
600
700
800 900 1000 1100 1200 1300
-1
W avenumber (cm )
Dr. Reinhart Job, University of
Hagen, Germany
Hydrogen Enhanced Thermal Donor Formation
IR-absorption
measurements:
Substrate:
5 cm Cz Si,
[P]  11015 cm-3
(n-type)
[Oi] = 1.21018 cm-3
H-Plasma:
8 h at 270 °C
1 h at 450 °C
µ-wave H-plasma
(1-step-process)
-1
Absorption Coefficient (cm )
verification of TDDs
(neutral species up to
the 5th generation)
16
14
a) H-plasma: T pl = 270 °C, t pl = 8 h
12
b) H-plasma: T pl = 450 °C, t pl = 1 h
10
n-Typ
8
Cz Si
Oi
6
4
2
b)
a)
0
400 420 440 460 480 500 520 540 560
-1
W avenumber (cm )
Dr. Reinhart Job, University of
Hagen, Germany
Hydrogen Enhanced Thermal Donor Formation
IR-absorption
measurements:
Substrate:
5 cm Cz Si,
[P]  11015 cm-3
(n-type)
[Oi] = 1.21018 cm-3
H-Plasma:
8 h at 270 °C
Annealing:
1 h / 4 h at 450 °C/air
(2-step-process)
-1
Absorption Coefficient (cm )
verification of TDDs
(neutral species up to
the 5th generation)
16
14
12
H-Plasm a:
n-Typ
Annealing:
T pl = 270 °C,
Cz Si
T tem p = 450 °C
t pl = 8 h
b) t tem p = 1 h
10 a) as plasm a
c) t tem p = 4 h
8
treated
Oi
6
4
c)
b)
2
a)
0
400 420 440 460 480 500 520 540 560
-1
W avenumber (cm )
Dr. Reinhart Job, University of
Hagen, Germany
Formation of Diodes by Thermal Donor Doping
• Substrates:
– p-type Cz Si (1.8 - 2.6  cm , 5 - 10  cm, 12 - 20  cm)
[B]  6 1014 cm-3 - 1.3 1016 cm-3
[Oi] = 7  8 1017 cm-3, [Cs] < 5 1016 cm-3
• TD formation (plasma treatment / annealing):
– H-plasma:
annealing:
µ-wave 2.45 GHz, tpl = 30 min, Tpl = 450 °C
no annealing
(1-step-process: TD-diode No. 1)
– H-plasma:
annealing:
110 MHz, 50 W, tpl = 60 min, Tpl = 250 °C
tann = 20 or 30 min, Tann = 450 °C/air
(2-step-process: TD-diodes No. 2, 3)
also alternative plasma hydrogenation possible:
– H-plasma:
DC, 500 V, Tpl = 400 - 450 °C, tpl  30 min
(1-step-process)
Dr. Reinhart Job, University of
Hagen, Germany
Formation of Diodes by Thermal Donor Doping
TD-diode (No. 1):
contact area: 1 mm2
10
7
10
6
I (A)
0,06
0,04
SR (  )
0,08
- SRP profile
p-n junction depth:
d = 40 µm
- I(V) curves at
T = RT
0,10
n-type
p-type region
region
10
5
p-n junction
Substrate:
12 - 20 cm Cz Si
0,02
H-Plasma:
30 min at 450 °C
µ-wave H-plasma
(1-step-process)
0,00
-100
10
4
0
-80
25
50
75
100
Depth (  m)
-60
-40
V BIAS (V)
Dr. Reinhart Job, University of
Hagen, Germany
125
-20
150
0
Formation of Diodes by Thermal Donor Doping
TD-diode (No. 2):
0,04
10
6
contact area: 1 cm2
Substrate:
12 - 20 cm Cz Si
H-Plasma:
60 min at 250 °C
Annealing:
30 min 450 °C/air
(2-step-process)
0,03
0,02
n-type region
SR (  )
- I(V) curves at
T = RT
I (A)
- SRP profile
p-n junction depth:
d  170 µm
10
5
p-n junction
0,01
10
4
0
0,00
-0,01
-100
p-type region
-80
50
100
150
200
Depth (µm)
-60
Dr. Reinhart Job, University of
Hagen, Germany
-40
V bias (V)
250
-20
300
0
Formation of Diodes by Thermal Donor Doping
TD-diode (No. 1):
contact area: 1 mm2
10
1
10
0
(1-step-process)
 Comparison
I(V) curves at T = RT:
 Data normalized
10
-1
10
-2
10
-3
10
-4
-2
I (Acm )
(2-step-process)
1)
2) TD-diode (2-step-process)
TD-diode (No. 2):
contact area: 1 cm2
1) TD-diode (1-step-process)
1)
2)
2)
-5
10
-100
-80
-60
to contact size !
Dr. Reinhart Job, University of
Hagen, Germany
-40
-20
V bias (V)
0
1
2
Analysis of TD-Diodes
TD-diode (No. 1):
0,10
contact area: 1 mm2
TD-Diode No. 1
0,08
- I(V) curves at
T = RT  150 °C
I (A)
0,06
0,04
Substrate:
12 - 20 cm Cz Si
0,02
H-Plasma:
30 min at 450 °C
µ-wave H-plasma
(1-step-process)
0,00
T = 22°C, 100°C, 150°C
-0,02
-100
-80
-60
-40
V BIAS (V)
Dr. Reinhart Job, University of
Hagen, Germany
-20
0
Analysis of TD-Diodes
TD-diode (No. 1):
- C(V) measurements
 C  V-3
 linearly graded
p-n junction
(if C  V-2  abrupt
junction)
Substrate:
12 - 20 cm Cz Si
H-Plasma:
30 min at 450 °C
µ-wave H-plasma
(1-step-process)
C (F)
linear slope 
6x10
-11
5x10
-11
4x10
-11
2,0x10
32
1,5x10
32
1,0x10
32
31
f = 1 MHz "reverse bias"
3x10
-11
2x10
-11
5,0x10
1x10
-11
0,0
-30
-25
-20
-15
V BIAS (V)
Dr. Reinhart Job, University of
Hagen, Germany
-10
-5
0
1/C³ (1/F³)
contact area: 1 mm2
Analysis of TD-Diodes / Wafer Mapping
TD-diode (No. 3):
"2-step-process":
contact area: 1 mm2
- 60 min H plasma at 260°C
- p-n junction depth:
d  100 µm
- 20 min annealing at 450°C/air
0,04
- I(V) curves,
mapping at T = RT
iu s
ra d
fe r
0,01
wa
H-Plasma:
60 min at 250 °C
Annealing:
20 min 450 °C/air
(2-step-process)
0,02
I (A)
Substrate:
12 - 20 cm Cz Si
0,03
0,00
-0,01
-25
-20
-15
-10
V bias (V)
Dr. Reinhart Job, University of
Hagen, Germany
-5
0
5
Summary
• appropriate plasma hydrogenation
 enhanced TD formation
• counter doping of p-type Cz Si can occurs due to TDs
 formation of deep p-n junctions (low thermal budget < 500 °C,
process time  1 hour)
• graded doping in n-type Cz Si
• p-n junction formation due to TDs  rapid and low thermal budget
technology for high voltage or power device applications
Dr. Reinhart Job, University of
Hagen, Germany