Advanced Silicon Processing & Manufacturing Techniques

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Module Number: 3

Title: Layer Deposition and Diffusion

Delivered by: University of Southampton

Module Credits: 15

Assessment Weighting:

  • Pre-residential work: 3
  • Post-residential work: 7
  • Examination: 10


  • Dr Daren Bagnell, University of Southampton


  • Professor Peter Ashburn
  • Dr Daren Bagnell
  • Dr Graham Ensell


  • Professor Vernon Morgan - University of Wales, Cardiff
  • Professor Nick Cowern - University of Surrey


  • Mr Robert Harper - IQE, Cardiff
  • Mr Paul Marron - Innos, Southampton
  • Dr Janet Bonar - Innos, Southampton

Industrial Advisors:

  • Mr Steve Byers - Innos, Southampton


The aim of this module is to present the science and technology of layer deposition and diffusion by exploring advanced technologies and introducing the Delegates to various deposition processes and properties during lectures, tutorials and cleanroom sessions.

Learning Objectives:

On successful completion of this module delegates will have gained an appreciation of:

  • the place of epitaxial growth techniques within the industry, and be able to compare and contrast the technology with other doping methods, e.g. ion implantation and diffusion
  • the elements of design and maintaining growth systems
  • the economic advantages and disadvantages of the technologies
  • the range and application of in-situ and ex-situ techniques available for layer characterisation


  • Pre-residential sessions: assignments 15 %
  • Post-residential sessions: assignments 35 %
  • Examination (supervised) 50 %

Background to the Module:

The epitaxial process is frequently the only fabrication route possible for the realisation of advanced devices. Lectures will be given by acknowledged experts from Universities and Industry. Each lecture is developed from basic concepts making the course intelligible to scientists and engineers of first degree level. Cleanroom sessions not only develop the lecture material but also widen the knowledge base covering all aspects of current practice.

Pre-Requisite Knowledge:

Diffusion mathematics, requires a basic understanding of simple differential equations, basic vectors are also needed. Some basic knowledge of chemistry is required in order to follow discussions on the CVD deposition of materials.

Delivery & Assignments:

  • Pre-residential sessions:
    • a study pack will be sent to Delegates covering the course
    • assignments will be set which carry 15% assessment marks
  • Residential week:
    • Lectures
    • Laboratory sessions
    • Tutorials/Case Studies
    • Exercises
  • Post- residential sessions:
    • advanced tutorial questions/case studies
    • written report (2000 - 4000 words)
    • supervised examination (3 questions out of 5, 2 hours)


  • Lectures 20 hours
  • Problem solving/Case study/Laboratory sessions 9 hours
  • Tutorials 3 hours
Topic Content
Basic mechanisms of atomic diffusion The mechanisms that play a part in the diffusion of atoms in solids, including the roles played by interstitials, vacancies, point defects and complexes
Diffusion calculations in silicon Using silicon as the material in which the diffusion is taking place, detailed calculations of the diffusion of the common dopants in silicon will be carried out
Diffusion in three dimensions Up until this point the module has been concerned with diffusion in two dimensions only. Now this will be extended to study the full three dimensions
Diffusion followed by
This is a commonly used process step in the semiconductor industry for the controlled incorporation of dopants in devices. This important processing step will be studied in depth
Advantages/disadvantages of diffusion Comparison of diffusion with other technologies. Dopants can be incorporated into silicon in ways other than standard diffusion. For example, they may be incorporated using ion-implantation, or they may be incorporated during growth itself in a CVD process. All these techniques will be compared and contrasted.
Introduction to deposition processes An introduction to deposition considering device requirements, material properties and deposition systems
CVD Systems Overview of chemical vapour deposition. The design and Vacuum requirements, materials compatibility issues. Equipment geometry for specific applications. Single wafer versus batch processing systems
Modelling of CVD processes The physical processes of gas transport in CVD systems. Boundary layers and gas diffusion
Polysilicon deposition The deposition and properties of polysilicon. How polysilicon is used in semiconductor devices including deep sub-micron bipolar transistors
Insulators, metals & applications As well as depositing semiconductor materials, CVD is also used for the deposition of insulating layers and metals for interconnects. The deposition of oxides, nitrides, oxynitrides, tungsten and copper will be discussed, along with their applications
Si and SiGe epitaxy The growth of single crystal silicon. CVD growth, material properties. Doping and control of material thickness. Uses of single crystal silicon in semiconductor devices. The properties and applications of SiGe in the semiconductor industry. SiGe for advanced bipolar and MOS devices. SiGe as a thin-film transistor material for flat panel display technology
New materials and processes A look at other semiconductor systems and materials that are beginning to find important applications
Guest Lecture

Professor Nick Cowern, University of Surrey

Guest Lecture Mr Robert Harper, IQE Silicon, Cardiff
Tutorial sessions Example classes, including question and answer sessions to support the lectured material
Clean Room Tour A tour of the Southampton Microelectronics Centre clean- room facility

Recommended Texts

  • "ULSI Technology", C Y Chang and S M Sze, (McGraw Hill, 1996 ISBN 0-07-114105-7)

  • "Semiconductor Devices, Physics and Technology", S M Sze (John Wiley & Co. 1981. ISBN 0-471-09837-X)

  • "SiGe heterojunction bipolar transistors", P.Ashburn,
    John Wiley & Co. 2003. ISBN 0-470-84838-3

NB: Order books early, often long delivery

Conference & Journal Papers

  • Successful selective epitaxial SiGe deposition process for HBT-BiCMOS and high mobility heterojunction pmos applications;
    R.Loo et al IEEE Trans. Elec. Dev. Vol: 36, No: 10 (2043) October 1989
    Journal Electrochemical Society, vol 150, No.10. pp638-647 (2003)

  • Transient enhanced diffusion of boron in silicon
    S. C. Jain, W. Schoenmaker, R. Lindsay, P. A. Stolk,
    S. Decoutere, M. Willander, and H. E. Maes
    Journal of Applied Physics vol 91, p8919 (2002)


NB: Details of content, timetable and lecturers maybe subject to change

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Module 3


09.00 - 10.00
Diffusion in three- dimensions
Introduction to deposition processes
Poly-Si deposition and properties
Si/SiGe epitaxy
Introduction to diffusion
10.00 - 10.30
10.30 - 11.30
Diffusion in a concentration gradient 1
Diffusion followed by drive-in
Principles of CVD
Poly-Si in IC processes
Si/SiGe epitaxy in bipolar processes
11.30 - 12.30
Diffusion in a concentration gradient 2

Guest Lecture
University of Surrey

Practical CVD Systems
Guest Lecture
IQE, Silicon
Si/SiGe epitaxy in MOS processes
12.30 - 14.00
14.00 - 15.00
Solutions to the basic diffusion equations
Advantages & disadvantages of diffusion
Modelling of CVD processes
Insulators, metals and applications
New Materials
15.00 - 16.00
Tutorial on diffusion
Concluding discussion
& 2nd tutorial on diffusion
Tutorial on CVD
Round up
16.00 - 17.00
Lab tour
(PM & JB)
Course Ends
(DB) Dr Dareen Bagnall - University of Southampton (NC) Prof. Nick Cowern - University of Surrey
(PA) Prof. Peter Ashburn - University of Southampton (RH) Mr Robert Harper - IQE, Silicon
(GLE) Dr Graham Ensell - University of Southampton (PM) Mr Paul Marron - Innos, Southampton
(VM) Prof. Vernon Morgan - University of Cardiff (JB) Dr Janet Bonar - Innos, Southampton
Enquiries and further information from:

Mrs Sandra Peace
IGDS Programme Co-ordinator,
IGDS Office
School of Electronics & Physical Sciences
University of Surrey

Tel +44 (0)1483 686 138
Fax +44 (0)1483 686 139
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