US006847060B2
(12)
(54)
United States Patent
(10) Patent N0.:
Welser et al.
(45) Date of Patent:
BIPOLAR TRANSISTOR WITH GRADED
5,903,018 A
BASE LAYER
6,031,256 A
6,150,667 A
-
-
_
9/2001 B1121
k
t 1.
................ .. 257/197
2001/0040244 A1
Charles R. LlltZ, Seekonk, MA (US);
2002/0027232 A1
3/2002 Shigematsu et al.
Kevin S. Stevens, Providence, RI (US)
2002/0102847 A1 *
8/2002 Sharps et al. ............. .. 438/681
~
~
-
11/2001 Fitzgerald et al. ........ .. 257/191
FOREIGN PATENT DOCUMENTS
FR
SutbJetct' to artiy (3115313111165, thte tiermgf tlgi;
pa en is ex en e or a Juse un er
JP
W0
2 795 871 A1
11312685
11/1999
WO 01/03194 A1
1/2001
1/2001
U-S-C- 154(b) by 0 days~
W0
WO 02/43155 A2
5/2002
This patent is subject to a terminal dis-
claimen
OTHER PUBLICATIONS
Pan, N., et al., “Pseudomorphic In—Graded Carbon Doped
GaAs Base Heterojunction Bipolar Transistors by Metal
(21) Appl. No.: 10/121,444
(22) Filed:
Apt 10’ 2002
(65)
IshiZaka et al. ............. .. 257/21
11/2000 T
Paul M- Deluca, Provldence, RI (Us);
-
( ) Notice.
2/2000 Liu et al. .................. .. 257/198
* 11/2000
6,285,044 B1
(73) Assignee: Kopin Corporation, Taunton, MA (US)
*
*J an. 25, 2005
5/1999 Shimawaki
6,150,677 A
(75) Inventors: Roger E‘ Weber’ PIOY1deHCe> RI (Us);
US 6,847,060 B2
Organic Chemical Vapor Deposition,”J0urnal of Electronic
Materials, 25(7):13 (1996).
Prior Publication Data
(List continued on neXt page.)
Primary Examiner—Nathan J. Flynn
Us 2002/0163014 A1 NOV‘ 7’ 2002
Assistant Examiner—Victor A. Mandala, Jr.
Re]ated U_S_ App?cation Data
(63)
(74) Attorney, Agent, or Firm—Hamilton, Brook, Smith &
Reynolds, PC.
Continuation-in-part of application No. 09/995,079, ?led on
(57)
ABSTRACT
Nov. 27, 2001, now Pat. No. 6,750,480.
(60)
Provisional application NO- 60/253459: ?led on N°V~ 27:
2000'
(51)
Im;_ C]_7 _______________ __ H01L 31/0328; H01L 31/0336;
gen. The disclosed semiconductor materials have a loW sheet
(52)
H01L 31/072; H01L 31/109; H01L 35/26
257/197. 257/191. 257/198.
resistivity because of the high carbon dopant concentrations
obtained. The material can be the base layer of gallium
us CL
""""""""""" "
(
58
)
F, M f S
1e
0
(56)
earc
h
’ 257006 257001’
arsenide-based heterojunction bipolar transistors and can be
257 191 197
lattice-matched to gallium arsenide emitter and/or collector
"""""""""""""""" "
’
layers by controlling concentrations of indium and nitrogen
257/198’ 200’ 201
/
’
in the base layer. The base layer can have a graded band gap
References Cited
that is formed by changing the How rates during deposition
of III and V additive elements employed to reduce band gap
relative to different III—V elements that represent the bulk of
the layer. The How rates of the III and V additive elements
U.S. PATENT DOCUMENTS
4,518,979
5,371,389
5,429,957
5,571,732
A
A
A
A
A semiconductor material Which has a high carbon dopant
concentration includes gallium, indium, arsenic and nitro
5/1985 Dumke et al.
12/1994 Matsuno et al.
7/1995 Matsuno et al.
maintain an essentially constant doping-mobility product
value during deposition and can be regulated to obtain
pre-selected base-emitter voltages at junctions Within a
11/1996 Liu
5,606,185 A
2/1997 Nguyen et al. ........... .. 257/197
5,814,843 A
9/1998 Ohkubo
5,858,818 A
1/1999 Ro et al.
resulting transistor.
22 Claims, 21 Drawing Sheets
5004 Si—doped museum“ (1 uo‘g CUTS)
500 5 Si-doped IHGGAS Grode <1 110'9 CUTE)
1500 A Si-dope: GaAs (5x101a cm'5)
500 A Si-doped InGoP (4 x lOWCrYfB)
5004600 A" C-doped G6,_x1nXAs,'yNy<15-4.5 X1019 W's)
7500 A Si-dopeci GaAs (1x10‘6 @163‘,
5000 4 8110020 GGAS (5 x10‘5cm'3)
GUAS SUBSTRATE
US 6,847,060 B2
Page 2
OTHER PUBLICATIONS
Ohkubo, M., et al., “Compositionally Graded C—doped
lnlixGaxAs Base in InP/InGaAs D—HBTs Grown by
MOCVD With LoW Base Sheet Resistance and High Current
Welser, RB, et al., “Turn—on Voltage Investigation of
GaAs—Based Bipolar Transistors With GalixlnxAsliyNy
Base Layers,” IEEE Electron Device Letters, 21(12):1—4
(2000).
Gain”, IEEE, pp. 641—644, 1997.
Stockman, S. A., et al., “Carbon Doping of lnxGalixAs By
MOCVD Using CCI4”, pp. 40—43, no date given.
Keiper, D., et al., “Metalorganic Vapour Phase Epitaxy
GroWth of InP—based Heterojunction Bipolar Transistors
With Carbon Doped InGaAs Base Using Tertiarybutylarsine
and
Tertiarybutylphosphine
in
N2
Ambient”,
XP—001030248, Jpn. J. Appl. Phys., vol. 39:6162—6165
LoW, T., et al., “InGaP HBT technology for RF and micro
Wave
instrumentation,”
Solid—State
Electronics,
(2000).
cence,” Appl. Phys. Lett., 64(1): 88—90 (1994).
Stillman, G. E., et al., “Carbon—doped InGaAs groWn by
MOCVD for InP/InGaAs heterojunction bipolar transis
tors”, Inst. Phys. Conf. Ser. No. 129:687—692 (1992).
Welser, et al., “LoW Vbe GaInAsN Base Heterojunction
43:1437—1444 (1999).
Liu, W., et al., “Current Transport Mechanism in GaInP/
GaAs Heterojunction Bipolar Transistors,” IEEE Transac
tions on Electron Devices, 40(8):1378—1383 (1993).
Lu, Z.H., et al., “Determination of band gap narroWing and
hole density for heavily C—doped GaAs by photolumines
Welser, RB, et al., “High Performance AlO_35GaO_65As/
GaAs
HBT’s,”
IEEE
Electron
Device
Letters,
21(5):196—199 (2000).
Bipolar Transistors,” IEICE Trans. Electron., E84—C(10):
1389—1393 (2001).
Welser, RB, et al., “Base Current Investigation of the
Long—Term Reliability of GaAs—Based HBTs,” GaAs Man
Kohama, et al., “Using Carbon Tetrachloride for Carbon
tech, (2000).
Doping AlxGalix As GroWn by Metalorganic Chemical
Vapor Deposition,” Jpn. J. Appl. Phys., 34(7A): 3504—3505
Patton, G.L., et al. “Graded—SiGe—Base, Poly—Emitter Het
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(1995).
Sugiura, et al., “Characterization of heavily carbon—doped
InGaAsP layers groWn by chemical beam epitaXy using
tetrabromide,” Applied Physics Letters, 73(12):2482—2484
(1998).
Bhat, et al., “Growth of GaAsN/GaAs, GaInAsN/GaAs and
GaInAsN/GaAs quantum Wells by loW—pressure organome
tallic chemical vapor deposition,” Journal of Crystal
Growth, 195: 427—437 (1998).
Chang, et al., “InGaP/InGaAsN/GaAs NpN double—hetero
junction bipolar transistor,” Applied Physics Letters,
76(16):2262—2264 (2000).
ters, 10(12):534—536 (1989).
Ida, M., et al., “InP/InGaAs DHBTs With 341—GhZ ft at high
current density of over 800 kA/cmz,” IEEE, (2001).
Kroemer, H., “Heterostructure bipolar transistors: What
should We build?” J. Vac. Sci. Technol., B1(2):126—130
(1983).
Fujihara, A., et al., “High—speed InP/InGaAs DHBTs With
Ballistic Collector Launcher Structure,” IEEE, (2001).
Nakahara, K., et al., “Continuous—Wave operation of long—
Wavelength GaInNAs/GaAs quantum Well laser,” Electronic
Welser, RB, et al., “Role of Neutral Base Recombination in
High Gain AlGaAs/GaAs HBT’s,” IEEE Transactions on
Letters, 32(17): 1585—1586 (1996).
Electron Devices, 46(8):1599—1607 (1999).
ing—Collector Heterojunction Bipolar Transistors (C—Up
MochiZuki, K., et al., “GaInP/GaAs Collector—Up Tunnel
Chang, P.C., et al., “InGaP/InGaAsN/GaAs NpN double—
TC—HBTs) : OptimiZation of Fabrication Process and Epi
heterojunction bipolar transistor,” Appl. Phys. Lett.,
taXial Layer Structure for High—Ef?ciency High—PoWer
76(16):2262—2264 (2000).
Ampli?ers,”
Ahmari, D.A., et al., “High—speed InGaP/GaAs HBT’s With
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* cited by examiner
on
Electron
Devices,
U.S. Patent
Jan. 25,2005
Sheet 5 0f 21
US 6,847,060 B2
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US 6,847,060 B2
DG0OCM0GVO9N0‘Om_x
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U.S. Patent
Jan. 25,2005
Sheet 8 0f 21
US 6,847,060 B2
500 A Si-doped hi0_6Ga0_4As(1 x 10l9 cm'3)
500 A Si-doped InGaAs Grade (1 x 1019 cm?)
1500 A Si-doped GaAs (S x 101301113)
500 A Si~d0ped lnGaP (4 x 1O'7cm'3)
50 A transitional layer
350 A C-doped graded (]211_XlnXAsl_yNy (3 - 7 x 10" cm‘3)
AEg compositional grade ~ 100 meV, averag? Es ~ 1.34 eV (80 meV lower than GaAs)
50 A transitional layer
2500 A Si-doped GuAs (1 X 1016 cm'3)
5000 A Si-dopcd GaAs (5 x lOlxcrn'j)
GaAs SUBSTRATE
High speed stmcture for f,(fmax) ~ 160 GHZ.
Bold = critical layers
FIG. 7B
U.S. Patent
Jan. 25,2005
Sheet 9 0f 21
US 6,847,060 B2
500 A Si-doped lnMGaMAs (l X 10[9 cm'3)
500 A Si-doped InGaAs Grade (1 x 1019 cm'3)
1500 A Si-doped GaAs(5 x 10‘3 cm'3)
500 A Si-doped lnGaP(4 X 10‘7 cn1'3)
50 A transitional layer
700 A C-doped Ga1_xInxAs,_yNy (4 x 1019mm
Alig compositional grade ~ 60 meV, average Eg ~ 1.24 eV (180 meV lower than GaAs)
S0 A transitional layer
7000 ~ 12000 A Si-doped GaAs (1 x 1016 cm")
5000 A Si-doped GaAs (5 X 1018 cm?)
GaAs SUBSTRATE
PA structure version 1 - no tunnel collector.
Bold = critical layers
FIG. 7C
U.S. Patent
Jan. 25,2005
Sheet 11 0f 21
US 6,847,060 B2
-F
_
r.
w
P
_
_-w
_.*
Ow
0%
we? we?
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0m
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0%
Omw
0w
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1,10% O m
_
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9.6H.
O0mOF
l‘:2%
m.OI
U.S. Patent
Jan. 25,2005
Sheet 13 0f 21
US 6,847,060 B2
0 DVDs TMIF=52O
CBr4 Flow
FIG. II
U.S. Patent
Jan. 25,2005
Sheet 14 0f 21
—20
-40
(DVemblVtea)
6 Dvbe
l1| t1l4
‘I
|
US 6,847,060 B2
a) Q
I!
q
I
I
I
I
420%“
y=O.1243x + 52393
—14@
500
550
600
650
700
750
TMIF
FIG. 12
800 850
900
950 1000
U.S. Patent
Jan. 25,2005
Sheet 15 0f 21
US 6,847,060 B2
Graded GaInAsN DHBT Epilayer Structure
Layer
Material
Thickness?)
D0ping(cm'3)
cap layer
GaojlnosAs
500
n> 1X1019
cap layer (gradcd)
GaXlnHAs X=O to 0.5
500
n>1x1019
emitter 1
GaAs
1000
n 5x1018
emitter 2
GaMInOjP
300
n 3x10l7
base
GaUq?nxAsUvwNy
Tb
p 41111019
collcctor
GaAs
4000
n 3x10l6
subcollector
GaAs
7000
n 5x10l8
500A<rh<1500A
x ~ 0.01 ~0.06
y~ .003
FIG. 13