MEMC
                       SUPPLEMENTAL EXECUTIVE PENSION PLAN
                                1997 RESTATEMENT


                                    ARTICLE I
                               HISTORY AND PURPOSE

     1.1 History.  Effective as of January 1, 1990, MEMC  Electronic  Materials,
Inc. ("MEMC") adopted the MEMC Electronic Materials, Inc. Supplemental Executive
Pension Plan (the  "Executive  Pension  Plan").  The Executive  Pension Plan was
amended effective June 14, 1991 to provide for lump sum distributions of amounts
less than  $25,000  at the  discretion  of the  Administrator,  and was  further
amended  effective  January 1, 1994 to provide that benefit accruals occur as of
the end of each Plan Year,  or on the date of the  Participant's  retirement  or
termination of employment if earlier. A Third Amendment,  effective December 17,
1993, provided for establishment of a Rabbi Trust for the Executive Pension Plan
to fund distributions under certain  conditions.  The Executive Pension Plan was
amended and  completely  restated in 1994.  MEMC now wishes to further amend and
restate the Executive Pension Plan to amend, among other things, the eligibility
provisions  of the  Plan,  and to  change  the  name  of the  Plan  to the  MEMC
Supplemental Executive Pension Plan.

     1.2 Purpose.  The  Executive  Pension  Plan is intended to provide  certain
benefits to  participants  who are  entitled to benefits  under the MEMC Pension
Plan  (the  "Pension  Plan")[prior  to  January  1,  1997,  the MEMC  Electronic
Materials,  Inc. Pension Plan for Salaried Employees and the MEMC Southwest Inc.
Pension Plan].  The benefits  provided by the Executive  Pension Plan to Pension
Participants  and their  Beneficiaries  shall be limited to that  portion of the
benefit  under the Pension  Plan which  would have been  payable but for certain
limitations  placed on such benefit in accordance  with the terms of the Pension
Plan.

     The Executive  Pension Plan is structured as two plans.  The portion of the
Executive  Pension Plan that provides  benefits based on limitations  imposed by
Section 415 of the Code is intended to be an "excess benefit plan" as defined by
Sections  3(36) and 4(b)(5) of the Employee  Retirement  Income  Security Act of
1974 ("ERISA"). The portion of the Executive Pension Plan that provides benefits
based on limitations imposed by Section 401(a)(17) of the Code is intended to be
a plan as defined by Sections 201(2), 301(a)(3) and 401(a)(1) of ERISA providing
benefits to a select group of management or highly compensated employees.

     1.3 Eligible  Participants.  This  Executive  Pension Plan shall  provide a
benefit only to an individual  who is an  "Employee,"  as defined in the Pension
Plan,  and (i) whose annual  "Earnings" as defined in Section 2.7 of the Pension
Plan,  exceed the compensation  limit set forth in Section  401(a)(17)(A) of the
Code,  as adjusted in  accordance  with  Section  401(a)(17)(B),  for any period
utilized in determining the individual's Accrued Benefit under the Pension Plan;
or (ii) whose Pension Plan benefit is reduced because of the limitations imposed
on such benefit by Section 415 of the Code.


                                   ARTICLE II
                                   DEFINITIONS

     2.1  (a)  Unless  otherwise  expressly  qualified  by the  context  of this
Executive Pension Plan, the terms used in this Executive Pension Plan shall have
the same meaning as those terms in the Pension Plan.

     (b) "Eligible  Participant" shall mean a Pension  Participant  described in
Section 1.3 for whom benefits under this Executive Pension Plan will be accrued.

     (c) "Pension Participant" shall mean a Participant in the Pension Plan.

     (d) "Pension Plan" shall mean the MEMC Pension Plan.

     (e) "Plan  Formula" shall mean the formula for computing the monthly amount
of the benefit  payable  under the Pension  Plan,  as amended from time to time,
that  is  applicable  to the  Eligible  Participant  whose  benefit  under  this
Executive Pension Plan is being computed.

     (f) "Rabbi  Trust" shall mean the trust  established  pursuant to the Trust
Agreement for MEMC Electronic  Materials,  Inc.  Supplemental  Executive Pension
Plan between MEMC Electronic Materials, Inc. and the trustee.


                                   ARTICLE III
                               RETIREMENT BENEFITS

     3.1 Limitations. The Executive Pension Plan provides benefits that would be
payable  to a  Pension  Participant  under  the  Pension  Plan  except  for  the
application of any one or more of the following two limitations:

     (a) Benefits not payable under the Pension Plan because of the  limitations
imposed  on the  maximum  amount  of  compensation  which may be  considered  in
determining  the  annual  benefit  of  the  Pension  Participant  under  Section
401(a)(17) of the Code ("Compensation Limitation"); and

     (b) Benefits not payable under the Pension Plan because of the  limitations
imposed on the annual  benefit of the Pension  Participant by Section 415 of the
Code ("Section 415 Limitation").

     3.2 Retirement Benefits.  Each Eligible Participant shall be entitled to an
annual retirement benefit under this Executive Pension Plan, payable in the form
as provided for in Article IV, equal to the excess of:

     (a) the  annual  retirement  benefit  which  would  have been  payable to a
Pension  Participant  under the Pension Plan without regard to the  Compensation
Limitation and the Section 415 Limitation; over

     (b) the amount of the annual retirement  benefit that is in fact payable to
such Pension Participant under the Pension Plan.

     To the extent they are not inconsistent  with this Executive  Pension Plan,
the provisions of the Pension Plan are incorporated by this reference and made a
part hereof.

     Notwithstanding  the above, in the event any portion of the accrued benefit
of an  Eligible  Participant  is awarded to an  Alternate  Payee  pursuant  to a
Qualified Domestic Relations Order, the participant's  annual retirement benefit
shall  be  adjusted,  as the Plan  Administrator  shall  determine,  so that the
combined  benefit  payable to the Eligible  Participant  and the Alternate Payee
from  this  Plan and the  Pension  Plan is the  amount  determined  pursuant  to
subsection 3.2(a) above.

     3.3  Offset.   Notwithstanding   anything  to  the  contrary,  the  benefit
determined in accordance  with Section 3.2 of this Executive  Pension Plan shall
be  reduced  by that  portion  of the  benefit  payable  from  any  nonqualified
retirement  plan  maintained  by  Monsanto  Company  or  International  Business
Machines,  Inc.  computed  as if  the  Eligible  Participant  had  received  his
retirement benefit under such plan or plans in the form of a Single Life Annuity
commencing  at his  Annuity  Starting  Date,  to the extent  that such  benefits
duplicate  the  benefit  determined  in  accordance  with  Section  3.2 of  this
Executive Pension Plan.

     3.4 Executive Pension Amount. The total amount of the benefit determined to
be payable to any  Eligible  Participant  in  accordance  with the terms of this
Article  III of the  Executive  Pension  Plan  shall be known as the  "Executive
Pension Amount."


                                   ARTICLE IV
                      PAYMENT OF EXECUTIVE PENSION AMOUNTS

     4.1 Form of  Payment.  The  normal  form of the  Executive  Pension  Amount
payable to an Eligible  Participant  under this Executive  Pension Plan shall be
the form of payment used to compute an Eligible Participant's accrued pension in
accordance with the terms of the Pension Plan.

     The  Executive  Pension  Amount  which  an  Eligible   Participant  or  his
Beneficiary  is entitled to receive under this  Executive  Pension Plan shall be
paid in the same form and,  subject to the provisions  below  applicable to lump
sum  distributions,  adjusted  by the same  factors  used to compute the form of
benefit in which he elects to receive his  retirement  income  payable under the
Pension  Plan;  provided,  however,  that a lump sum payment  must be elected as
described  below.  If, however,  the lump sum actuarial  equivalent value of the
Executive  Pension Amount payable under the Executive  Pension Plan is less than
$25,000,  or alternately,  if the monthly amount of the Executive Pension Amount
payable  under  the  Executive   Pension  Plan  is  less  than  $250,  the  Plan
Administrator may, in its sole discretion,  pay such amount in a single lump sum
cash  payment.  Payment  of the  lump  sum so  determined  shall  be in full and
complete  satisfaction  of all  benefits  due the  Eligible  Participant  or his
Beneficiary  in  accordance  with the terms of this  Executive  Pension Plan. An
Eligible  Participant who receives a lump sum distribution from the Pension Plan
and who is not entitled to a lump sum distribution  under this Executive Pension
Plan shall receive the Executive Pension Amount in the normal form, as described
in the Pension Plan.

     Notwithstanding  anything  to the  contrary  in this  Section,  an Eligible
Participant  may elect to receive  the  actuarial  equivalent  of the  Executive
Pension  Amount that he or his  Beneficiary  is  entitled to receive  under this
Executive Pension Plan:

     (a) As a lump sum payment; or

     (b) In annual installments over a period not in excess of 15 years.

Such an  election  shall be made in  writing  in a form  prescribed  by the Plan
Administrator  no later than six (6) months before the payment is to commence in
accordance with Section 4.3 of this Executive  Pension Plan. A new  distribution
election shall revoke all prior elections;  provided,  however,  no distribution
election  shall be valid if such election is filed within six months of the date
any  amount  shall  become  payable  under  this   Executive   Pension  Plan.  A
distribution  election shall be void  automatically  if the Participant does not
retire by the end of the eighth month  following the month in which the election
is made.  Payment of a lump sum  pursuant to an election  hereunder  shall be in
full and complete  satisfaction  of all benefits due an Eligible  Participant or
his Beneficiary in accordance with the terms of this Executive Pension Plan.

     The amount of a lump sum payment shall be the actuarial equivalent value of
the normal form of benefit  payable to the  Participant  in accordance  with the
first paragraph of this Section 4.1, using the actuarial  assumptions  described
in the  definitions of Actuarial  Equivalent in the Pension Plan as of the month
in which such an election is made.

     In the event the Eligible  Participant  elects an installment or an annuity
form of  distribution,  the  Employer  shall  pay the  lump sum  present  value,
calculated as described  above,  of the Executive  Pension Amount into the Rabbi
Trust not later than the Eligible Participant's retirement date.

     4.2 Death  Benefits.  Each  Eligible  Participant  entitled to an Executive
Pension  Amount  under this  Executive  Pension Plan who dies before his Annuity
Starting  Date  shall be  entitled  to a death  benefit  equal in  amount to the
additional  death  benefit  to which the  Eligible  Participant  would have been
entitled  under the Pension Plan if the Executive  Pension  Amount as determined
under Article III was payable  under the Pension Plan instead of this  Executive
Pension Plan.

     Payment of any death benefit under the Executive Pension Plan shall be made
to the  persons  and in the  proportions  to which any death  benefit  under the
Pension  Plan is or  would  be  payable  (disregarding  any  Qualified  Domestic
Relations Order).  Payment of any death benefit shall be a single payment of the
lump sum present value of the death benefit.  If an Eligible  Participant elects
to receive installment  payments, as provided in Section 4.1, and dies after his
Annuity  Starting  Date but before all  installment  payments have been made, or
elects a lump sum benefit and dies after his  Annuity  Starting  Date but before
payment has been made, the remaining payment(s) shall be made to the Beneficiary
or  Beneficiaries  designated by the Eligible  Participant on a form provided by
the  Administrator  and  filed  with the  Administrator  prior  to the  Eligible
Participant's  death.  In the event no  designation is made or if no Beneficiary
survived  the  Eligible  Participant,  payment  shall  be made  to the  Eligible
Participant's surviving spouse, and if the Eligible Participant leaves no spouse
surviving, to the estate of the Participant.

     4.3 Time of Payment. Payment of the Executive Pension Amount to an Eligible
Participant  under this  Executive  Pension Plan shall commence and terminate on
the same date or dates on which the retirement income payable to such individual
under the Pension Plan  commences and  terminates,  unless such  individual  has
received a lump sum payment or has elected annual installment payments from this
Executive  Pension Plan in accordance  with Section 4.1 and such form of benefit
is not available to the Eligible  Participant  under the Pension Plan.  Lump sum
payments  shall  be  made as soon as  administratively  feasible  following  the
Eligible  Participant's   retirement,   or  such  later  date  as  the  Eligible
Participant shall specify pursuant to Section 4.4. Annual  installment  payments
shall  commence as soon as  administratively  feasible  following  the  Eligible
Participant's  retirement,  or such later date as the Eligible Participant shall
specify on the election form described in Section 4.1, and  thereafter  shall be
made on the anniversaries of such date until the number of installment  payments
elected have been made.

     Payment of any lump sum death benefit of an Eligible  Participant  shall be
made as soon as  administratively  feasible,  but in no event later than six (6)
months after the date of the Eligible Participant's death.

     Notwithstanding  any  other  provision  of this  Plan to the  contrary,  no
Executive Pension Amount shall be paid to any Eligible  Participant prior to the
earliest date on which MEMC's  federal  income tax deduction for such payment is
not precluded by Section  162(m) of the Internal  Revenue Code. In the event any
payment is delayed solely as a result of the preceding restriction, such payment
shall be made as soon as  administratively  feasible following the first date as
of which  Section  162(m) of the Internal  Revenue Code no longer  precludes the
deduction  by MEMC of such  payment.  Amounts  deferred  because of the  Section
162(m) deduction limitation shall be increased by simple interest for the period
of delay at the annual rate of six percent (6%).

     4.4 Deferral of Lump Sum Payment.  Notwithstanding  anything in Section 4.3
to the contrary,  an Eligible  Participant  who validly elects to receive a lump
sum  payment in  accordance  with  Section  4.1 may elect to defer  receipt to a
designated future year following  retirement.  Such an election shall be made in
writing in a form  prescribed  by the Plan  Administrator  no later than six (6)
months before the Eligible Participant's retirement date. Such an election, once
made,  shall be irrevocable.  A lump sum payment deferred in accordance with the
provisions  of this Section 4.4 shall be  increased  by simple  interest for the
period of deferral at the annual rate of three percent (3%).


                                    ARTICLE V
                               SOURCES OF PAYMENTS

     Benefits  payable  under this  Executive  Pension Plan shall be paid by the
Employer  of each  Eligible  Participant  out of its general  assets  (except as
provided  below with respect to a Rabbi Trust).  Obligations to pay benefits due
Eligible  Participants  under the Executive  Pension Plan shall primarily be the
obligation of the Employer.  An Eligible  Participant  shall not have any rights
with respect to benefits  from the  Employer  under the  Executive  Pension Plan
other than the unsecured right to receive payments from the Employer. Except for
the  obligation  to fund a Rabbi  Trust as set forth in Section  4.1,  or by the
terms of the Rabbi  Trust,  an  Employer  shall not be  obligated  to set aside,
earmark or escrow any funds or other assets to satisfy its obligation under this
Executive Pension Plan. Any benefit payable in accordance with the terms of this
Executive  Pension  Plan shall not be  represented  by a note or any evidence of
indebtedness other than the promises contained in this Executive Pension Plan.

     If any  Eligible  Participant  is entitled  to receive a benefit  from this
Executive  Pension  Plan,  based on his  employment  with  more  than one of the
Employers  (that  is,  more than one of the  business  entities  that  adopt the
Pension  Plan) then each such  Employer  shall pay that portion of the Executive
Pension Amount that bears the same ratio to the total Executive  Pension Amount,
as the  benefits  accrued by such  Eligible  Participant  under the Pension Plan
while in the  employment  of each  such  Employer  bears to the  total  benefits
accrued  under the  Pension  Plan;  provided,  however,  that the  portion of an
Eligible  Participant's  benefit  payable  under  this  Executive  Pension  Plan
attributable  to service  with an Employer  (or  Employers)  that is no longer a
member of the Controlled Group which includes MEMC Electronic  Materials,  Inc.,
as defined in Sections 414(b), (c) and (m) of the Internal Revenue Code of 1986,
as amended, at the time such individual  terminates  employment with all members
of such group shall be paid by MEMC Electronic  Materials,  Inc. The Sponsor may
make a single payment to the Eligible Participant and receive reimbursement from
the Employers.

     MEMC  Electronic  Materials,  Inc. and any other  Employer may  establish a
Rabbi  Trust to  accumulate  assets  to fund  the  obligations  of the  Employer
pursuant to this Executive Pension Plan. Payment from the Rabbi Trust of amounts
due under the terms of this Executive  Pension Plan shall satisfy the obligation
of the respective Employer(s) to make such payment out of its general assets. In
no event shall any  Eligible  Participant  be entitled to receive  payment of an
amount from the  general  assets of an Employer  that the  Eligible  Participant
received from the Rabbi Trust.  No Employer  shall be obligated to contribute to
the Rabbi Trust except as specifically provided in Section 4.1.


                                   ARTICLE VI
                               PLAN ADMINISTRATOR

     6.1 Plan Administrator. The Executive Pension Plan shall be administered by
the same  Committee  appointed  by MEMC  Electronic  Materials,  Inc. to be Plan
Administrator  of the MEMC Pension  Plan.  The Plan  Administrator  so appointed
shall have all of the  authority,  rights and duties to administer the Executive
Pension Plan as is assigned to the  Committee to  administer  the Pension  Plan;
provided,  however,  that such  Committee  may adopt  such  rules as it may deem
necessary,  desirable and appropriate to administer the Executive  Pension Plan.
Except as provided in the Rabbi Trust, the decisions of the Committee, including
but not limited to interpretations  and determinations of amounts due under this
Executive Pension Plan, shall be final and binding on all parties.

     6.2  Standard of Conduct.  The  Committee  shall  perform its duties as the
Committee in its sole discretion  shall determine is appropriate in light of the
reason and purpose  for which the  Executive  Pension  Plan is  established  and
maintained.  Except as provided in the Rabbi Trust,  the  interpretation  of all
plan provisions and the determination of whether a Participant or Beneficiary is
entitled to any benefit  pursuant to the terms of the  Executive  Pension  Plan,
shall be exercised by the Committee in its sole discretion.

     Any Employer that adopts and maintains this  Executive  Pension Plan hereby
consents to actions of the Committee made in its sole discretion.


                                   ARTICLE VII
                            NONALIENATION OF BENEFITS

     Except as may be required by the federal income tax withholding  provisions
of the  Code  or by the  tax  laws  of any  State,  the  interests  of  Eligible
Participants and their  beneficiaries  under this Executive Pension Plan are not
subject  to the  claims  of  their  creditors  and  may  not be  voluntarily  or
involuntarily sold, transferred,  alienated,  assigned, pledged, anticipated, or
encumbered.  Any attempt by an Eligible  Participant,  his  Beneficiary,  or any
other person to sell, transfer, alienate, assign, pledge, anticipate,  encumber,
charge or otherwise  dispose of any right to benefits payable hereunder shall be
void. An Employer may cancel and refuse to pay any portion of a benefit which is
sold, transferred, alienated, assigned, pledged, anticipated or encumbered.


                                  ARTICLE VIII
                            AMENDMENT AND TERMINATION

     MEMC  Electronic  Materials,  Inc.  reserves  the right to amend,  alter or
discontinue this Executive Pension Plan at any time; provided,  however, that no
such amendment,  alteration of discontinuance shall decrease the Accrued Benefit
of any Eligible Participant accrued to the date of such amendment, alteration or
discontinuance or the right of an Eligible Participant to payment of such amount
and that assets of any Rabbi Trust established  pursuant to Article IV shall not
revert to MEMC Electronic  Materials,  Inc. until all benefit obligations funded
by such assets determined  separately with respect to each Eligible  Participant
and his Beneficiary,  shall have been fulfilled.  Such action to amend, alter or
discontinue  this  Executive  Pension  Plan may be taken by the MEMC  Electronic
Materials,  Inc.  Employee Benefit Committee or such other entity as may be duly
authorized by the Board of Directors of the Sponsor.


                                   ARTICLE IX
                               GENERAL PROVISIONS

     9.1 Plan Not a Contract of Employment. This Executive Pension Plan does not
constitute a contract of employment,  and participation in the Executive Pension
Plan will not give any  Eligible  Participant  the right to be  retained  in the
employment of any of the Employers.

     9.2  Construction  of Terms.  Words of gender  shall  include  persons  and
entities of any gender, the plural shall include the singular,  and the singular
shall include the plural.  Section  headings exist for reference  purposes only,
and shall not be construed as part of the Executive Pension Plan.

     9.3  Successors.  The  provisions of this  Executive  Pension Plan shall be
binding  upon the  Employers  and their  successors  and  assigns and upon every
Eligible   Participant   and  his  heirs,   beneficiaries,   estates  and  legal
representatives.

     9.4  Official  Actions.  Any  action  required  to be taken by the Board of
Directors of MEMC Electronic  Materials,  Inc. pursuant to the Executive Pension
Plan may be performed by any person or persons,  including a committee, to which
the Board of Directors of the MEMC  Electronic  Materials,  Inc.  delegates  the
authority  to take  actions  of that  kind.  Whenever  under  the  terms of this
Executive  Pension Plan an entity  corporation  is permitted or required to take
some action such  action may be taken by an officer of the  corporation  who has
been duly  authorized  by the Board of  Directors  of such  corporation  to take
actions of that kind.

     9.5 Controlling  State Law. To the extent not superseded by the laws of the
United  States,  the laws of the State of Missouri  shall be  controlling in all
matters relating to this Executive Pension Plan.

     9.6  Severability.  In case any  provision of this  Executive  Pension Plan
shall be held illegal or invalid for any reason,  such  illegality or invalidity
shall not affect the remaining provisions of the Executive Pension Plan, and the
Executive  Pension Plan shall be  construed  and enforced as if such illegal and
invalid provisions had never been set forth.

     9.7  Withholding.  The Employer  shall withhold from amounts due under this
Executive  Pension Plan the amount  necessary to enable the Employer to remit to
the  appropriate  government  entity  or  entities  on  behalf  of the  Eligible
Participant as may be required by the federal income tax withholding  provisions
of the Code, by an  applicable  state's  income tax, or by an  applicable  city,
county or  municipality's  earnings or income tax act. The Employer may withhold
from the compensation of, or collect from, the Eligible  Participant any amounts
due from an Eligible Participant, the amount necessary to remit on behalf of the
Eligible  Participant  any FICA  taxes  which may be  required  with  respect to
amounts  accrued by an  Eligible  Participant  hereunder  as  determined  by the
Employer.

     The undersigned  hereby  certifies that the foregoing Plan  restatement was
duly  adopted  by  MEMC  Electronic  Materials,  Inc.  by its  Employee  Benefit
Committee in accordance  with the authority  delegated to such  Committee by the
Board of Directors.


                                        MEMC ELECTRONIC MATERIALS, INC.



                                         By: /s/ Margaret B. Stonum
                                             ---------------------------------

                                                 Director, Benefits
                                         Title: ------------------------------

                                                 April 30, 1997
                                         Date: -------------------------------