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Section 12

HEATER MODULES 12Heater Modules 162

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163162 +44 (0)1323 811188 sales@uhvdesign.comwww.uhvdesign.comHeaters Should your requirements fall outside our standard specifications then please contact us at:

Heater Modules

A cost-effective solution to sample heating

whilst benefiting from proven cutting-edge heater

technology. They comprise CVD processed heating

elements packaged in refractory metal cases.

Key Advantages

» High uniformity heating to 1200°C

» Elements with large radiating surface to gap ratio – able to run at lower temperatures than conventional metal heaters

» Refractory metal hot zone – uncompromised performance at high temperatures

Thermocouples

Heater modules are available with type ‘C’ or ‘K’

thermocouples and can be supplied with semiconductor

grade quartz guards to protect the heater element from

mechanical damage, i.e. accidental contact with the sample

transfer tool. Type C (Tungsten/Rhenium) thermocouples

are provided as standard. For applications in which the use

of Tungsten or Rhenium would be undesirable, a type K

(Chromel/Alumel) thermocouple can be supplied.

In addition to the complete sample heating solutions

offered in the EpiCentre section (page 148) UHV Design

also offers a range of individual heater modules for end

users to incorporate into their own heater stage designs.

The range provides end users with a cost-effective solution

to sample heating, whilst benefiting from a proven heater

technology used in market leading stages.

Heater Module Overview

UHV Design heater modules are used in vacuum

applications for radiantly heating semiconductor wafers,

holder supported samples or various other substrates to

high temperatures. The modules feature CVD processed

heating elements packaged in refractory metal cases.

The immediate hot zone holding the element is constructed

from refractory metals such as Molybdenum, Tantalum

and ceramics and does not include any other materials

to compromise performance at high temperature. These

modules are therefore particularly suitable for ultra-high

vacuum applications. 12

Choosing the right elementUntil recently, graphite heaters have been used in the majority of deposition stages and are still the mainstay providing robust performance in UHV applications such as MBE. However, graphite heaters oxidise and are consumed when run in the presence of high partial pressures of O2 at high temperature. For sputtering applications which involve high partial pressures of O2, other technologies are also available with superior performance.

SiCg Elements

Solid Silicon Carbide coated Graphite elements provide improved durability when using oxidising atmospheres by comparison with PgG. Being an insulating form of SiC, holes are required in the coating to make electrical connection and the underlying Graphite is exposed and vulnerable to oxidation at these locations.

sSiC Elements

Solid Silicon Carbide elements (see Figure 1) are manufactured from a conducting solid SiC material in the ß phase and are more robust in all respects. They are durable to mechanical or electrical shocking, reactive gas/oxidation immunity at temperature. They are also optimised to give the very best in temperature uniformity. By virtue of the large radiating surface to gap ratio, all these elements run at considerably lower temperatures than often used metal wire heaters which ensures heater longevity. The typical ratio of heated element surface to meander gap is >5:1 resulting in excellent substrate heating uniformity, even without rotation.

UHV Heater Technology

Relative Performance of Heater Technologies Rated on a scale of 1(Low) -5 (High)

Technology SiC Coated Elements Solid ßSiC Heaters

Characteristic Silicon Carbide coated

GraphiteSolid Silicon Carbide

UHV Performance 5 5

Ultimate achievable temperature 4 4

Oxidation resistance 4 5

Mechanical robustness 2 4

Cost 3 5Figure 1.Solid Silicon Carbide (sSiC) heater element option.

165164 +44 (0)1323 811188 sales@uhvdesign.comwww.uhvdesign.comHeaters Should your requirements fall outside our standard specifications then please contact us at:

Specification Table

HEATER MODULE SIZE HM-25* HM-50 HM-75 HM-100 HM-150 HM-200**

A (dia) 50.0 78.0 111.0 136.0 180.0 230.0

B (pcd) 34.0 63.8 89.8 115.3 157.3 204.5

C 20.8 43.3 43.3 43.3 43.3 78.0

D 12.0 25.0 25.0 12.5 25.0 45.0

E 6.0 12.5 12.5 20.0 12.5 22.5

F 18.0 34.8 35.6 38.0 38.0 38.0

G 15.5 20.0 20.0 20.0 20.0 30.0

H 19.0 20.7 26.7 26.7 26.7 26.7

I 40.0 50.0 50.0 50.0 50.0 50.0

J M2.5 M4 M4 M4 M4 M4

DE

G

(PO

WE

R T

ER

MIN

ALS

)P

CD

B

H C

-VE THERMOCOUPLEM3 TERMINAL

+VE THERMOCOUPLEM3 TERMINAL

SUPPORT LEGS

A

F I SUPPORT

LEG LENGTH

10

7

J

M4

REFRACTORY METAL ENCLOSURE

M4 POWER TERMINALS (CONNECT WITH 0.5X15 Mo OR Ta FOIL)

HM SERIES

A B PCD C D E F G H I J

HM-25 50 34 20.8 12 6 18 15.5 19 40 M2.5

HM-50 78 63.75 26.7 17.4 11.2 38 30 26.7 50 M4

HM-75 112.5 89.75 26.7 17.4 11.2 38 30 26.7 50 M4

HM-100 137.7 115.25 26.7 17.4 11.2 40.7 30 26.7 50 M4

HM-150 180.5 157.25 78 45 22.5 38 30 26.7 50 M4

HM-200 230 204.5 78 45 22.5 38 30 26.7 50 M4

Heater Module Part Code Generator

Heater Module

+ Sample Size + Heater Element + Thermocouple Type

HM 25mm* or 1" wafer/sample size 25 Silicon carbide coated graphite SiC Type C, Tungsten Rhenium C

50mm or 2" wafer/sample size 50 Solid Silicon Carbide sSiC Type K, Chromel Alumel K

75mm or 3" wafer/sample size 75

100mm or 4" wafer/sample size 100

150mm or 6" wafer/sample size 150

200mm** or 8" wafer/sample size 200Example Configured Part Number: HM-50-SiC-C= Heater Module HM, 50mm/2" wafer/sample size 50, Silicon Carbide coated Graphite

heating element SiC, Type C Thermocouple CNOTE: *25mm Sample Size on SSiC options only.

**200mm and larger available on request.

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NOTE: *25mm Sample Size on SSiC options only. **200mm and larger available on request - dimensional information for the HM-200 is for illustrative purposes only..

ELEMENT MATERIAL

SAMPLE SIZECOLD

RESISTANCE Ω (20°C)

HOT RESISTANCE Ω (1000°C)

ELECTRICAL CHARACTERISTICS AT 1000°C

WATTS AMPS VOLTS

SiC Coated Graphite 2" 1.4 1.2 840 26.5 31.7

3" 1.7 1.1 1150 32.3 35.6

90mm (EC282) 2.9 1.9 850 21.2 40.2

100mm 1.6 1 1500 38.7 38.7

150mm 1.8 1.3 2500 43.9 57.0

200mm 2.2 1.45 3600 49.8 72.2

Solid SiC 1" 9.5 5.5 400 8.5 46.9

2" 10 5.7 840 12.1 69.2

3" 10 5.7 1150 14.2 81.0

90mm (EC282) 12 7 850 11.0 77.1

100mm 12 7 1500 14.6 102.5

150mm 12 7 2500 18.9 132.3

Quick Reference Guide: Typical Standard Heater Element Resistance

Heater Module Power Supplies

For details of compatible power supply and temperature controller packages contact sales@uhvdesign.com.