Recitals

First Amendment to Credit Agreement

by SunEdison
October 22nd, 1998

   1
                                                               EXHIBIT 10 DDD(1)
                       FIRST AMENDMENT TO CREDIT AGREEMENT

     This First Amendment to Credit Agreement  ("First  Amendment") is effective
as of  September 1, 1998 between  MEMC  ELECTRONIC  MATERIALS,  INC., a Delaware
corporation  ("Borrower"),  as the Borrower, and HULS AG, a company formed under
the laws of the Federal Republic of Germany ("Huls"),  as the sole Lender and as
Agent.

                                    Recitals

     WHEREAS,  Borrower  and Huls entered  into a Credit  Agreement  dated as of
December  1, 1996 (the  "Credit  Agreement")  pursuant  to which Huls  agreed to
extend up to US$75,000,000 of credit to Borrower on a term basis;

     WHEREAS,  Borrower,  Huls and  certain  affiliates  of Huls have  agreed to
extend additional  credit to Borrower and to restructure the existing  financing
provided by Huls and its affiliates to Borrower, and

     WHEREAS, as part of such restructuring,  Borrower and Huls desire to change
the interest rate payable by Borrower to Huls under the Credit Agreement.

     NOW THEREFORE,  in consideration  of the foregoing  premises and the mutual
covenants and conditions hereinafter set forth, the parties agree as follows:

     1. The  definitions  of  "Applicable  Margin",  "Base  Rate",  "Performance
Level",  "Performance Level I", "Performance Level II",  "Performance Level III"
and  "Performance  Level IV" in Section 1.01 of the Credit  Agreement are hereby
deleted in their entirety.

     2. The following  definitions  are hereby  inserted in proper  alphabetical
order into Section 1.01 of the Credit Agreement:

          "Applicable  Spread" means a percentage  per annum equal to the excess
     of (a) the Bloomberg  fair market  sector  curves  (adjusted for the chosen
     interest  rate method)  applicable  two business  days prior to the Initial
     Termination Date to a B3 rated industrial  borrower for the period from the
     Initial  Termination  Date  through the latest  possible  Termination  Date
     (taking into account, if applicable, the latest Extension Termination Date)
     over (b) the corresponding Swap Rate for such period.

          "Extension Certificate" has the meaning specified in Section 2.15.

          "Extension  Period Interest Rate" means two business days prior to the
     Initial Termination Date, (a) either the British Bankers' Association (BBA)
     LIBOR rate (as shown on the Reuters page FRBD or comparable  pages) for the
     12-month  period or the Swap Rate for the  24-month  period or the 36-month
     period  commencing from the Initial  Termination  Date as follows:  (i) the
     36-month period for Advances  subject to an Initial  Termination Date on or
     prior to December 31, 1998, (ii) the 24-month  period for Advances  subject
     to an Initial  Termination  Date on or prior to December 31, 1999, or (iii)
     the 12-month period for all other Advances, plus (b) the Applicable Spread.

          "Extension Request Notice" has the meaning set forth in Section 2.15.

          "Extension  Termination Date", if any, means the earlier of (a) either
     (i) the first anniversary of the Initial Termination Date, or (ii) if there
     has been an earlier  applicable  Extension  Termination Date on or prior to
     December  31,  1999,  the  first   anniversary  of  such  prior   Extension
     Termination  Date,  or  (iii)  if  there  has  been an  earlier  applicable
     Extension  Termination  Date  after  December  31,  1999  and on or  before
     December  31,  2000,  the  first   anniversary  of  such  prior   Extension
     Termination  Date  and (b) the  termination  in  whole  of the  Commitments
     pursuant to Section 2.04 or Section 6.01; provided,  that in no event shall
     an Extension Termination Date be after December 31, 2001.

          "Initial Termination Date" for any Advance means December 1, 2004.

          "Replacement Financing Arrangement" means a financing arrangement with
     any  Person who is not an  Affiliate  of the  Borrower  or the Agent or any
     Lender on  substantially  the terms which would apply hereunder  during the
     period from the then  applicable  Termination  Date to the latest  possible
     Extension  Termination  Date,  provided  that  the  interest  rate  of such
     Replacement  Financing  Arrangement  shall be no higher than the  Extension
     Period Interest Rate and, if no lesser interest rate is available, shall be
     the Extension Period Interest Rate.

          "Swap Rate" means the US-Dollar  denominated  interbank  interest rate
     swap  rates/LIBOR  offered  rates as shown on  Reuters  page ICAP and other
     comparable  brokerage  pages,  adjusted for the chosen interest rate method
     (annual/semi-annual compounding, etc.).

     3. The definition of "Change of Control Date" in Section 1.01 of the Credit
Agreement is hereby  deleted in its entirety and the following is substituted in
lieu thereof:

          "Change of Control  Date" means the date of  occurrence of a Change of
     Control;  provided,  that if such  occurrence  is on or prior to January 1,
     2001, the occurrence shall be deemed to have occurred on January 1, 2001.


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     4. The  definition  of  "Eligible  Assignee"  in Section 1.01 of the Credit
Agreement is hereby  deleted in its entirety and the following is substituted in
lieu thereof:

          "Eligible  Assignee"  means any Person approved by all of the Lenders;
     provided,  however,  that neither the Borrower  nor any  Subsidiary  of the
     Borrower shall qualify as an Eligible Assignee.

     5. The  definition of  "Termination  Date" set forth in Section 1.01 of the
Credit  Agreement  is  hereby  deleted  in its  entirety  and the  following  is
substituted in lieu thereof:

          "Termination  Date"  means  the  earlier  of (a)  either  the  Initial
     Termination Date or, if applicable,  the Extension Termination Date and (b)
     the  termination  in whole of the  Commitments  pursuant to Section 2.04 or
     Section 6.01.

     6. Section 2.03 of the Credit Agreement shall be amended as follows: in the
fifth line, "1/8 of 1%" is hereby deleted and "1/4 of 1%" is substituted in lieu
thereof.

     7.  Section  2.06(a)  of the  Credit  Agreement  is hereby  deleted  in its
entirety and the following is substituted in lieu thereof:

          "(a)  Interest on the  Advances.  From  September 1, 1998,  until such
     principal  amount shall be paid in full, the Borrower shall pay interest on
     the unpaid principal  amount of the Advances,  if any, which interest shall
     be  payable  semiannually,  at an  interest  rate  per  annum  equal to the
     applicable  rate for each  Advance as listed on Schedule A hereto under the
     heading  "Interest  Rate";   provided,   however,   that,  if  the  Initial
     Termination  Date is on or after January 1, 2001, as of the date  occurring
     45 Business  Days after the Change of Control  Date,  the interest rate per
     annum shall be the higher of (x) the  applicable  rate for each  Advance as
     listed on Schedule A hereto under the heading  "Interest  Rate" and (y) the
     rate  determined  under clause (a) of the  definition  of Extension  Period
     Interest Rate, determined as of the Change of Control Date (rather than the
     Initial  Termination Date), plus the Applicable Spread;  provided,  that in
     the event of an extension of the then  applicable  Termination  Date to the
     Extension  Termination Date pursuant to Section 2.15 hereto,  from the then
     applicable Termination Date to the Extension Termination Date, the interest
     rate per annum shall be equal to the Extension Period Interest Rate."

     8. Section 2.07  (Interest  Rate  Determination  Upon Change of Control) is
hereby deleted in its entirety and the following is substituted in lieu thereof:
"SECTION 2.07. RESERVED."

     9. The  following  Section 2.15 is hereby added at the end of Article II of
the Credit Agreement:

          "SECTION 2.15. Extension. If the then applicable Termination Date is a
     date on or before  December  31, 2000 and the  Borrower may desire that the
     Lenders  extend  the  then  applicable  Termination  Date to the  Extension
     Termination  Date,  then (a) the Borrower shall give written notice of said
     fact (the "Extension Request Notice") to the Agent and the Lenders no later
     than four (4) months before the  Termination  Date,  (b) the Borrower shall
     use its best  efforts  to obtain and enter into on or before the date which
     is two  months  prior  to the  Termination  Date  a  Replacement  Financing
     Arrangement  and  (c)  if  the  Borrower  shall  not  have  entered  into a
     Replacement Financing Arrangement on or before the date which is two months
     prior to the Termination  Date, the Borrower shall deliver to the Agent and
     the Lenders a certificate of the Borrower (the "Extension Certificate") (x)
     certifying  that the Borrower has not entered into a Replacement  Financing
     Arrangement, but the Borrower used its best efforts to do so as required by
     clause (b) and setting forth such evidence and back-up  detail as necessary
     to demonstrate the efforts made,  including a written letter from each bank
     from which a Replacement  Financing  Arrangement  as required by clause (b)
     was  requested,  indicating  that Borrower made such a request and that the
     request  was  denied,  and (y)  requesting  that  the  Termination  Date be
     extended to the Extension  Termination  Date. For purposes of this Section,
     the Borrower  shall be deemed to have complied with the  requirement to use
     its "best  efforts"  by  requesting  from and,  if  applicable,  diligently
     negotiating a Replacement  Financing  Arrangement as required by clause (b)
     with each of three (3) commercial  banks that are nationally  recognized in
     the United States and each have total assets in excess of  $20,000,000,000.
     The Agent shall have the right to designate,  within ten (10) Business Days
     after  receipt  of an  Extension  Request  Notice,  one of the three  banks
     referred  to in the  preceding  sentence.  For  purposes  of this  Section,
     diligent  negotiation  shall mean  negotiation  in good  faith and  without
     denial or unreasonable delay of any reasonable request by any such bank for
     information in connection with its consideration of providing a Replacement
     Financing  Arrangement  to Borrower.  For the  avoidance of doubt,  nothing
     herein is  intended  to  prevent  Borrower  from  obtaining  a  Replacement
     Financing  Arrangement  on terms  equal to or better  than  those  provided
     hereunder.

          Following receipt of the Extension  Certificate,  the Agent and/or the
     Lenders  shall have the right  (without any  obligation to do so) to obtain
     for the Borrower a Replacement  Financing  Arrangement on terms equal to or
     better than those provided hereunder.


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          If the Borrower has (a) delivered the Extension  Request Notice within
     the time period  specified  above,  (b) used its best efforts to obtain and
     enter into a Replacement  Financing Arrangement and delivered the Extension
     Certificate within the time period specified above and (c) not unreasonably
     or in bad faith refused to enter into a Replacement  Financing  Arrangement
     (with terms equal to or better than those provided  hereunder) obtained for
     the Borrower by the Agent or any of the Lenders  pursuant to the  preceding
     paragraph,  the  Termination  Date  shall  be  extended  to  the  Extension
     Termination  Date  and the  interest  rate  shall be the  Extension  Period
     Interest  Rate.  The Agent shall provide the Borrower with a written notice
     setting forth the Extension Period Interest Rate.

          The Borrower  shall be  responsible  for the payment of any  customary
     commitment  fee and other fees in connection  with  obtaining a Replacement
     Financing Arrangement.

          For the avoidance of doubt, in no event shall an Extension Termination
     Date be requested by the Borrower  after  December 31, 2000 or be on a date
     after December 31, 2001."

     10. Section 5.02 of the Credit Agreement is deleted in its entirety and the
following is substituted in lieu thereof:

          "SECTION 5.02. Negative Covenants.  On and after September 1, 1998 and
     so long as any Advance  shall  remain  unpaid or any Lender  shall have any
     Commitment  hereunder,  the  Borrower  will not,  unless the Lenders  shall
     otherwise consent in writing:

               (a) Liens,  etc.  Create or suffer to exist, or permit any of its
          Subsidiaries to create or suffer to exist, any lien, security interest
          or other  charge or  encumbrance,  or any other  type of  preferential
          arrangement,  upon or with respect to any of its  properties,  whether
          now owned or  hereafter  acquired,  or  assign,  or permit  any of its
          Subsidiaries to assign,  any right to receive income,  in each case to
          secure any Debt of any Person, other than:

                    (i)  purchase   money  liens  or  purchase   money  security
               interests  upon  or in  any  property  acquired  or  held  by the
               Borrower or any Subsidiary in the ordinary  course of business to
               secure  the  purchase   price  of  such  property  or  to  secure
               indebtedness  incurred  solely for the purpose of  financing  the
               acquisition of such property;

                    (ii) liens or security  interests  existing on such property
               at the time of its  acquisition  (other  than  any  such  lien or
               security interest created in contemplation of such acquisition);

                    (iii) liens for taxes, assessments and government charges or
               levies  to the  extent  not  required  to be paid  under  Section
               5.01(b) hereof;

                    (iv)   liens   imposed  by  law,   such  as   materialmen's,
               mechanics',  carriers', workmen's and repairmen's liens and other
               similar liens arising in the ordinary course of business securing
               obligations  that are not  overdue  for a period  of more than 30
               days;

                    (v) pledges or deposits to secure obligations under workers'
               compensation  laws or similar  legislation or to secure public or
               statutory obligations;

                    (vi)  easements,  rights  of way and other  encumbrances  on
               title to real  property  that do not render title to the property
               encumbered  thereby  unmarketable or materially  adversely affect
               the use of such property for its present purposes; and

                    (vii) liens incurred or deposits made in the ordinary course
               of business to secure the performance of letters of credit, bids,
               tenders, sales contracts,  leases, surety, appeal and performance
               bonds and other  similar  obligations  not incurred in connection
               with the borrowing of money;

               provided,  that the aggregate principal amount of the Debt, other
               indebtedness, taxes, assessments,  governmental charges or levies
               or other obligations  secured by the liens or security  interests
               referred to in clauses (i) through (vii) of this Section  5.02(a)
               shall  not  exceed  $45,000,000  in the  aggregate  at  any  time
               outstanding.

                    (b) Accounting Changes. Make or permit, or permit any of its
               Subsidiaries to make or permit, any change in accounting policies
               or reporting  practices,  except as allowed by generally accepted
               accounting principles."

     11. Unless otherwise  provided herein,  any term in initial capital letters
or all  capital  letters  used as a defined  term but not  defined in this First
Amendment shall have the meaning set forth in the Credit Agreement.


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     12.  Except as  modified  herein,  all terms and  conditions  of the Credit
Agreement shall remain in full force and effect.

     13. This First  Amendment shall be governed by, and construed in accordance
with, the laws of the State of New York.

     14. This First Amendment may be executed in any number of counterparts  and
by  different  parties  hereto in separate  counterparts,  each of which when so
executed  shall be deemed an  original  and all of which  taken  together  shall
constitute one and the same agreement. Delivery of any executed counterpart of a
signature  page to this First  Amendment  by  telecopier  shall be  effective as
delivery of a manually executed counterpart of this First Amendment.

     IN WITNESS WHEREOF,  the parties hereto have caused this First Amendment to
be executed by their duly authorized representatives effective as of the day and
year first above written.


MEMC ELECTRONIC MATERIALS, INC., as Borrower


By: /s/ Kenneth L. Young
    -----------------------------------
      Name:  Kenneth L. Young
      Title: Treasurer


HULS AG, as Agent


By: /s/ Georg Muller
    -----------------------------------
      Name:  Georg Muller
      Title:


By: /s/ Jurgen Buchsteiner
    -----------------------------------
      Name:  Jurgen Buchsteiner
      Title:


HULS AG, as the sole Lender


By: /s/ Georg Muller
    -----------------------------------
      Name:  Georg Muller
      Title:


By: /s/ Jurgen Buchsteiner
    -----------------------------------
      Name: Jurgen Buchsteiner
      Title:

   5
                                   Schedule A
                                       to
                       First Amendment to Credit Agreement


                         New Interest Rates per Advance

                          (effective September 1, 1998)

Advance Date                  Advance Amount                      Interest Rate
____________                  ______________                      _____________

13 Dec 1996                   $30,000,000                                9.422%

23 Dec 1996                    20,000,000                                9.622%

10 Jan 1997                    25,000,000                                9.722%