Need of new semiconductor material

woundcallousSemiconductor

Nov 1, 2013 (3 years and 9 months ago)

90 views

Diamond as a future semiconductor material

By
-
Aditya D. Dekhane

Need of new semiconductor
material

Need of new semiconductor
material


High operating temperatures



High power applications



Better electrical and electronic properties


Moore’s law

The driving
force for
innovations!!!

Why ‘Diamond’?

0
500
1000
1500
2000
2500
3000
3500
4000
4500
5000
Melting point
Debye temperature
0
5
10
15
20
25
Thermal
conductivity
(W/cm°C)
Thermal
diffusivity
(cm^2/s)
Thermal
expansion coeff.
(e-6)
0
2
4
6
8
10
12
14
Break down
voltage (e6)
(V/cm)
Energy band
gap (ev)
Dielectric
constant
Electron
mobility
(e3)(cm^2/V)
Silicon
Diamond
GaN
GaAs
Diamond

Same
valency as
Silicon i.e.4





Very strong
SP
3
C
-
C

bonds


Inert for
chemical
attack!!!


Ref: Lecture notes;


Solid State Physics, http://www.lcst
-
cn.org/Solid%20State%20Physics/Ch18.html

Doping of diamond

Needs to be doped for
-


Better electrical properties


To be used in diodes, transistors


1.
P
-
type doping


Boron (B)


Sometimes natural diamonds are already ‘p’ doped


Boron is the best acceptor for diamond


Energy band gap 0.2
-
0.3 eV


Boron enters as a substitutional impurity


Doping of diamond continued…

2
. N
-
type doping

Nitrogen


Most successful


Energy gap 1.7 eV


Insulators at room
temperature due to
deep energy gap



Phosphorus


Shallow energy level dopant


Energy band gap 0.5 eV


Electron mobility raised by
~100 cm
2
/V


Sometimes interfere with
electrical properties



Sulfur


Energy level 0.37 eV


Electron mobility raised
by ~600 cm
2
/V


Still under development


Lithium


As an interstitial
impurity


Still under development

Doping techniques

1. Chemical Vapor Deposition (CVD)


Impurity atoms incorporated in diamond during the growth
of diamond films.


Vapors containing impurity elements


APCVD, LPCVD, PECVD!!!!


Impurity

Impurity
source

Solvent
gas

Impurity/Carbon
atom ratio (ppm)

Temp.

(
°
C)

Pressure

(Torr)

Reference

Boron

B
2
O
3

Ethanol

10000

800

100

[1]

Nitrogen

N
2

CH
4

50000

800

100

[1]

Phosphorous

PH
3

CH
4

1000
-
20000

950

80

[2]

Doping techniques continued…

2. Ion implantation


High

energy dose of ions bombarded, breaks existing bonds
and creates new


CIRA (Cold Implantation Rapid Annealing) and


RTI (Room Temperature Implantation)


Dopant

Process
name

Dose

(cm
-
2
)

Energy (KeV)

Annealing
temperature
(
°
C)

Annealing
time

(min)

Reference

Nitrogen

CIRA

10
13

40
-
640

1400

10

[3]

Phosphorus

CIRA

10
16

84
-
165

1200

-

[4]

Boron

CIRA

10
16

30
-
60

600

-

[4]

Lithium

RTI

10
16

40
-
50

900

60

[5]

Successful applications

1. Dual substrates by SP
3
technologies Inc
.


2
. Diamond semicondutor by Nippon Telegraph and Tele. Corp., Japan


Formed a semiconductor with 81 GHz frequency, aiming at 300GHz with 30
W/mm power for practical usage.



3. MEMS technology using Ultra
Nanocrystalline

Diamond (UNCD)


Diamond materials Inc. developed UNCD doped 3% with nitrogen


Manufacturing with CVD method and reactive ion etching technique for
etching diamond


Ref: [6], [7], [8]


Interview with company


Interview with company continued...


Company representative


Ms. Nga Vu (Application Process Engineer)


Company
-

SP
3

diamond technologies, Santa Clara, CA 95054


Contact no.
-

+1
-
877
-
773
-
9940 Ext. 209


Email
-

nvu@sp3inc.com



Details of telephonic and email conversation
:


Diamond

wafers

are

manufactured

on

a

substrate

Si,

SiO
2
,

W,

WC,

graphite


The

diamond

is

deposited

on

substrates

by

CVD

method

at

~
600
-
900
°
C


Coefficient

of

thermal

expansion

(CTE)

mismatch


Wafers

successfully

manufactured

are

of

4
”,

6
”,

8


and

12


sizes
.


Boron

as

p
-
type

dopant
.


Nitrogen

as

n
-
type

dopant
.


Sheet

resistance

method

is

used

to

predict

the

percentage

of

boron



More

the

amount

of

boron

more

risk

of

interference

with

diamond

properties
.


Facility

can

manufacture

micro

as

well

as

nano

grained

diamond

wafers
.


Summary


Diamond

has

the

best

property

combination

(Electrical,

Mechanical)

to

be

a

future

semiconductor

material
.



Research

work

is

necessary

to

develop

n
-
type

doping

methods



Reviewed

information

in

paper

is

verified

with

industry

person

and

is

under

practical

use
.


Manufacturing

techniques

need

to

be

developed

which

are

still

costly

for

industrial

scale

production
.



References

1.
Yoshiyuki

Show,

et

al
.
,

Structural

changes

in

CVD

diamond

film

by

boron

and

nitrogen

doping
.

Diamond

and

related

materials,

2000
.

9
(
3
-
6
)
:

p
.

337
-
340
.

2.
S
.

Koizumi,

et

al
.
,

Growth

and

characterization

of

phosphorous

doped

{
111
}

homoepitaxial

diamond

thin

films
.

Applied

physics

letters,

1997
.

71
(
1065
)
.

3.
R
.

Kalish,

C
.

Uzan
-
Saguy,

and

B
.

Philosoph,

Nitrogen

doping

of

diamond

by

ion

implantation
.

Diamond

and

related

materials,

1997
.

6
:

p
.

516
-
520
.

4.
Prins,

J
.
F
.
,

Doping

of

diamond

by

the

diffusion

f

interstitial

atoms

into

layers

containing

a

low

density

of

vacancies
.

Diamond

and

related

materials,

1998
.

7
:

p
.

545
-
549
.

5.
R
.

Job,

et

al
.
,

Electrical

properties

of

lithium
-
implanted

layers

on

synthetic

diamond
.

Diamond

and

related

materials,

1996
.

5
:

p
.

757
-
760
.

6.
Jerry

W
.

Zimmer

and

G
.

Chandler,

SOD

Substrates



The

Next

Step

in

Thermal

Control,

sp
3

Diamond

Technologies

Inc
.

7.
Hara,

Y
.

NTT

verifies

diamond

semiconductor

operation

at

81

GHz
.

2003
.

8.
John

A
.

Carlisle

and

N
.
D
.

Kane,

Commercializing

Diamond

RF

MEMS

Devices
.

IEEE

Microwave

magazine,

2007
:

p
.

62
.




Any questions???

Dr. Gordon E. Moore, Intel museum