EXHIBIT 10f
                                                                     -----------


                           --------------------------

                             KEY EMPLOYEE AGREEMENT

                           --------------------------




To:    Mr. Michael DeLuca                                      As of May 1, 1997
       12 Glen Gery Road
       Shrewsbury, Massachusetts  01545


         The  undersigned,  Applied  Science and  Technology,  Inc.,  a Delaware
corporation,  as well as its  successors and assigns  (hereinafter  collectively
referred to as the "Company"), hereby agree with you as follows:

         l. Position and Responsibilities.

            1.1 You  shall  serve  as Vice  President  of  Manufacturing  of the
Company (or in such other  capacity  as shall be  designated  by the  President,
Senior Vice  President of  Operations,  or Board of Directors  and be reasonably
acceptable to you). You will, to the best of your ability, devote your full time
and best efforts to the  performance  of your duties  hereunder and the business
and affairs of the Company and perform such executive  duties as may be assigned
to you by or on authority of the Company's President or Senior Vice President of
Operations  from time to time and the duties  customarily  associated  with such
capacity  from time to time and at such  place or places  as the  Company  shall
designate are appropriate and necessary in connection with such employment.

            1.2 You will duly, punctually and faithfully perform and observe any
and all  rules and  regulations  which the  Company  may now or shall  hereafter
establish governing the conduct of its business.

            1.3 You will report directly to the Company's  Senior Vice President
of Operations.

         2. Term of Employment.

            2.1 The initial term of this  Agreement  shall be for the period set
forth on Exhibit A annexed hereto  commencing with the date hereof.  Thereafter,
this Agreement  shall be  automatically  renewed for  successive  periods of one
year,  unless you or the Company shall give the other party not less than thirty
(30) days written notice of non-renewal. Your employment with the Company may be
terminated as provided in Section 2.2 .

            2.2 The Company shall have the right, upon written notice to you, to
terminate your employment:







                           (a)  immediately  at any time for "Cause" (as defined
         herein  subject to your right of cure and right to dispute as  provided
         in Section 2.3 herein); or

                           (b) at any time,  without "Cause,"  provided that the
         Company  shall be  obligated to pay to you the  Severance  Benefits set
         forth in  Sections 6 or 7, as  applicable,  of Exhibit A, plus any sums
         then  due to you,  including  those  expenses  as are  provided  for in
         Section 8 of Exhibit A, less (i)  applicable  taxes and other  required
         withholdings, and (ii) any amounts you may owe to the Company. Payments
         under  this  Section  2.2 (b)  shall not be due or  payable  if you are
         terminated  at any time for "Cause" or if you  voluntarily  resign from
         your employment, except as set forth in Section 7 of Exhibit A.

            2.3 For purposes of Section  2.2,  the term  "Cause"  shall mean (a)
gross  negligence or willful  misconduct in the performance of assigned  duties;
(b)  material  and  repetitive  refusal to perform  or  discharge  the duties or
responsibilities   assigned  by  the  President  or  Senior  Vice  President  of
Operations  of the  Company  provided  the same are not  illegal,  unethical  or
inconsistent  with  the  position  of  Vice  President  of  Manufacturing  of  a
corporation  and the failure to correct  such refusal and perform such duties or
responsibilities  within a  reasonable  period of time (but in any event no less
than  seven  (7)  calendar  days  after  written  notice of such  failure);  (c)
conviction of a felony or misdemeanor involving moral turpitude;  (d) willful or
prolonged  absence  from work not excused by a bona fide medical  disability  as
reasonably  determined by a qualified  physician mutually acceptable to both you
and the  Company or other good cause as  reasonably  determined  by the Board of
Directors;  and (e) falseness of any warranty or representation by you herein or
the breach of your obligations under this Agreement to the material detriment of
the Company.  Any dispute,  controversy,  or claim arising out of, in connection
with,  or in  relation  to  the  definition  of  "Cause"  shall  be  settled  by
arbitration in accordance with the terms of Section 17 hereof.

            2.4 In the  event of the  Involuntary  Termination  (as  hereinafter
defined) of your  employment  with the Company at any time,  the Company  hereby
agrees to provide you with Severance Benefits as defined in Section 6 of Exhibit
A hereto or payments in the event of a "Change in Control" as defined in Section
7 of Exhibit A. In this regard, the phrase "Involuntary  Termination" shall mean
(a) any termination of your employment by the Company other than for "cause," as
defined  in  Section  2.3,  (b) any  notice  by the  Company  not to renew  this
Agreement pursuant to Section 2.1, or (c) for purposes of Section 7 of Exhibit A
(but not Section 6 of Exhibit A) any  termination of your  employment by you due
to any of the  following  circumstances:  (i) a reduction in your Base Salary or
Company-paid  benefits,  (ii) a reduction  in your  eligibility  for any Company
bonus or other benefit program,  (iii) a material or substantial  change in your
title,  position,  authority or duties, or (iv) a change of your principal place
of employment to a location beyond thirty (30) miles of Woburn, Massachusetts.

            2.5 You shall have the right to terminate  this  Agreement  upon not
less than thirty (30) days prior written notice to the Company.



                                      -2-






         3. Compensation.   You shall receive the  compensation and benefits set
forth on Exhibit A  ("Compensation")  for all  services  to be  rendered  by you
hereunder  and for your  transfer of property  rights  pursuant to an  agreement
relating  to  proprietary  information  and  inventions  of even  date  herewith
attached  hereto as  Exhibit C between  you and the  Company  (the  "Proprietary
Information and Inventions Agreement").

         4. Other Activities During Employment.

            4.1 Except for any outside  employments and directorships  currently
held by you as listed on Exhibit B, and except with the prior written consent of
the Company's Board of Directors, you will not during the term of this Agreement
undertake or engage in any other employment,  occupation or business  enterprise
other than one in which you are an inactive investor.

            4.2 You hereby agree that,  except as disclosed on Exhibit B hereto,
during your employment hereunder,  you will not, directly or indirectly,  engage
(a) individually,  (b) as an officer, (c) as a director, (d) as an employee, (e)
as a consultant,  (f) as an advisor,  (g) as an agent  (whether a salesperson or
otherwise),  (h) as a broker,  or (i) as a partner,  coventurer,  stockholder or
other  proprietor  owning  directly or  indirectly  more than two  percent  (2%)
interest, in any firm, corporation,  partnership,  trust, association,  or other
organization  which  is  engaged  in  the  research,  development,   production,
manufacture  or marketing of equipment or processes in direct  competition  with
the  Company or any other  line of  business  engaged  in or under  demonstrable
development  by  the  Company  (such  firm,  corporation,   partnership,  trust,
association,   or  other  organization  being  hereinafter   referred  to  as  a
"Prohibited  Enterprise").  Except  as may be shown  on  Exhibit  B, you  hereby
represent  that  you are not  engaged  in any of the  foregoing  capacities  (a)
through (i) in any Prohibited Enterprise.

         5. Former Employers.

            5.1 You  represent  and warrant that your  employment by the Company
will not  conflict  with and will not be  constrained  by any  prior or  current
employment,  consulting  agreement or relationship  whether oral or written. You
represent and warrant that you do not possess  confidential  information arising
out of any such employment,  consulting agreement or relationship which, in your
best  judgment,  would be utilized in  connection  with your  employment  by the
Company in the absence of Section 5.2.

            5.2 If, in spite of the second  sentence of Section  5.1, you should
find that confidential information belonging to any other person or entity might
be usable in connection with the Company's business,  you will not intentionally
disclose  to the  Company  or use on  behalf  of the  Company  any  confidential
information  belonging  to  any  of  your  former  employers;  but  during  your
employment  by the  Company you will use in the  performance  of your duties all
information  which is  generally  known and used by persons  with  training  and
experience  comparable to your own all information  which is common knowledge in
the industry or otherwise legally in the public domain.



                                      -3-









         6. Proprietary  Information  and  Inventions.   You  agree to  execute,
deliver  and be bound  by the  provisions  of the  Proprietary  Information  and
Inventions Agreement.

         7. Post-Employment Activities.

            7.1 For a period  of two (2) years  (or for a lesser  period  should
the Company so determine)  after the termination or expiration,  for any reason,
of your  employment  with the  Company  hereunder,  absent the  Company's  prior
written  approval,  you will not  directly or  indirectly  engage in  activities
similar or reasonably related to those in which you shall have engaged hereunder
during the two years  immediately  preceding  termination or expiration for, nor
render  services  similar or  reasonably  related to those  which you shall have
rendered  hereunder  during such two years to, any person or entity  whether now
existing or hereafter  established  which directly competes with (or proposes or
plans to directly compete with) the Company ("Direct Competitor") in any line of
business engaged in or under  development by the Company.  Nor shall you entice,
induce  or  encourage  any of the  Company's  other  employees  to engage in any
activity  which,  were it  done  by you,  would  violate  any  provision  of the
Proprietary  Information  and Inventions  Agreement or this Section 7 or to work
with you in any other  organization.  As used in this Section 7.1, the term "any
line of  business  engaged  in or under  development  by the  Company"  shall be
applied as at the date of termination of your  employment,  or, if later,  as at
the date of termination of any post-employment consultation.

            7.2 For a period of two (2)  years  after  the  termination  of your
employment  with the Company,  the provisions of Section 4.2 shall be applicable
to you  and you  shall  comply  therewith.  As  applied  to  such  two (2)  year
post-employment period, the term "any other line of business engaged in or under
development  by the Company," as used in Section 4.2, shall be applied as at the
date of termination of your  employment with the Company or, if later, as at the
date of termination of any post-employment consultation with the Company.

            7.3 No  provision of this  Agreement  shall be construed to preclude
you from  performing  the same services  which the Company hereby retains you to
perform for any person or entity which is not a Direct Competitor of the Company
upon the expiration or termination  of your  employment (or any  post-employment
consultation)  so long as you do not thereby violate any term of the Proprietary
Information and Inventions Agreement.

         8. Remedies.  Your  obligations  under the Proprietary  Information and
Inventions Agreement and the provisions of Sections 4, 6, 7, 8, 9 and 17 of this
Agreement  (as  modified  by  Section  10,  if  applicable)  shall  survive  the
expiration or termination of your employment  (whether  through your resignation
or otherwise)  with the Company.  You  acknowledge  that a remedy at law for any
breach  or  threatened  breach  by  you  of the  provisions  of the  Proprietary
Information and Inventions Agreement or Section 7 hereof would be inadequate and
you  therefore  agree that the Company  shall be entitled to such  injunctive or
other equitable relief in case of any such breach or threatened breach.



                                      -4-






         9.  Assignment.  This  Agreement and the rights and  obligations of the
parties  hereto  shall  bind  and  inure  to the  benefit  of any  successor  or
successors of the Company by  reorganization,  merger or  consolidation  and any
assignee of all or substantially all of its business and properties, but, except
as to any such successor or assignee of the Company,  neither this Agreement nor
any rights or  benefits  hereunder  may be  assigned  by the  Company or by you,
except  by  operation  of  law.  The  Company's  obligations  and  those  of any
successors or assignees of the Company under this  Agreement,  including but not
limited to the severance  provisions and other  compensation and benefits due to
you pursuant to Exhibit A hereto, will be a condition of and are to remain those
of any successor or assignee.

         10.  Interpretation.  IT IS THE INTENT OF THE PARTIES  THAT in case any
one or more of the provisions contained in this Agreement shall, for any reason,
be held to be invalid, illegal or unenforceable in any respect, such invalidity,
illegality  or  unenforceability  shall not affect the other  provisions of this
Agreement,  and this Agreement shall be construed as if such invalid, illegal or
unenforceable  provision had never been contained  herein.  MOREOVER,  IT IS THE
INTENT OF THE PARTIES THAT in case any one or more of the  provisions  contained
in this  Agreement  shall for any reason be held to be  excessively  broad as to
duration,  geographical  scope,  activity or subject,  such  provision  shall be
construed  by limiting  and  reducing it as  determined  by a court of competent
jurisdiction,  so as to be enforceable to the extent  compatible with applicable
law.

         11. Notices.  Any notice which the Company is required to or may desire
to give you shall be given by personal delivery or registered or certified mail,
return  receipt  requested,  addressed to you at your address of record with the
Company,  or at such  other  place as you may  from  time to time  designate  in
writing.  Any notice which you are required or may desire to give to the Company
hereunder  shall be given by personal  delivery or by  registered  or  certified
mail,  return  receipt  requested,  addressed  to the  Company at its  principal
office,  or at such other office as the Company may from time to time  designate
in  writing.  The date of  personal  delivery  or the date of mailing any notice
under this Section 11 shall be deemed to be the date of delivery thereof.

         12.  Waivers.  If either party should waive any breach of any provision
of this  Agreement,  such party  shall not  thereby be deemed to have waived any
preceding  or  succeeding  breach  of the same or any  other  provision  of this
Agreement.

         13. Complete Agreement; Amendments. The foregoing including Exhibits A,
B and C hereto,  is the entire  agreement  of the  parties  with  respect to the
subject matter hereof,  superseding any previous oral or written communications,
representations,  understandings,  or agreements with the Company or any officer
or  representative  thereof.  Any  amendment to this  Agreement or waiver by the
Company of any right hereunder shall be effective only if evidenced by a written
instrument  executed by the parties hereto,  upon authorization of the Company's
Board of Directors.

         14.  Headings.  The  headings of the  Sections  hereof are inserted for
convenience  only and shall not be deemed to  constitute  a part  hereof  nor to
affect the meaning of this Agreement.



                                      -5-







         15.  Counterparts.  This  Agreement may be signed in two  counterparts,
each of which  shall be  deemed an  original  and both of which  shall  together
constitute one agreement.

         16.  Governing Law. This  Agreement  shall be governed by and construed
under Massachusetts law.

         17.  Arbitration  of Disputes.  Subject to the rights of the parties to
seek injunctive relief as described herein, any controversy or claim arising out
of, or relating to, any provision of this Agreement  shall be settled by binding
arbitration in accordance with the laws of the  Commonwealth of Massachusetts by
three  arbitrators,  one of whom shall be appointed by the Company,  one of whom
shall be appointed by you,  and the third  arbitrator  who shall be appointed by
the first two  arbitrators.  If the first two  arbitrators  cannot  agree on the
appointment of a third arbitrator,  then the third arbitrator shall be appointed
by the American Arbitration  Association in the City of Boston. Such arbitration
shall be  conducted  in the City of Boston in  accordance  with the rules of the
American  Arbitration  Association,  except  with  respect to the  selection  of
arbitrators,  which shall be as provided in this Section.  Judgment on the award
or  determination  rendered  by the  arbitrators  shall be  final,  binding  and
conclusive upon the parties, and may be entered in any court having jurisdiction
thereof and shall not be appealable.  The prevailing  party in such  arbitration
proceeding  shall  be  entitled  to  reimbursement  by the  other  party  of all
reasonable  legal  fees and other  costs  incurred  by the  prevailing  party in
connection with such proceeding,  including any legal fees and costs incurred in
connection with the enforcement of any award.

         18. Advice of Separate Counsel.  The Company has requested that the law
firm of  O'Connor,  Broude &  Aronson  prepare  this  document  on behalf of the
Company.  You  acknowledge  that you have been advised to review this  Agreement
with your own legal  counsel and other  advisors of your choosing and that prior
to entering into this  Agreement,  you have had the  opportunity  to review this
Agreement  with your  attorney and other  advisors and have not asked (or relied
upon) O'Connor, Broude & Aronson to represent you in this matter.






                    [THIS SPACE IS INTENTIONALLY LEFT BLANK]


                                      -6-







         If you are in agreement with the foregoing, please sign your name below
and also at the bottom of the Proprietary  Information and Inventions Agreement,
whereupon  this  Agreement  shall become  binding in accordance  with its terms.
Please then  return  this  Agreement  to the  Company.  (You may retain for your
records the accompanying counterpart of this Agreement enclosed herewith).



ACCEPTED AND AGREED:                       APPLIED SCIENCE AND TECHNOLOGY, INC.




                                           By:        
--------------------------------              ----------------------------------
Michael DeLuca                                Dr. Richard S. Post, President



                                      -7-





                                                                       EXHIBIT A

                   EMPLOYMENT TERM, COMPENSATION AND BENEFITS
                                OF MICHAEL DeLUCA

         l. Term.  The term of the Agreement to which this Exhibit A is attached
and made a part shall be for a period  from the date of this  Agreement  through
April 30, 1998.

         2. Compensation.

            (a)  Base  Salary.   Your  base  salary  ("Base  Salary")  shall  be
$120,000.00  per annum  through April 30, 1998,  payable in accordance  with the
Company's  payroll  policies  at  the  rate  of  $$4,615.38  every  other  week.
Commencing  April 1, 1998, your Base Salary shall be established by the Board of
Directors= Compensation Committee.

            (b) Bonuses.  Fiscal 1998. The Company shall  establish  appropriate
incentive  compensation  plans ("Bonuses") for you each fiscal year that you are
employed  hereunder,  commencing  with Fiscal 1998 which  commences  on June 29,
1997,  under  which you shall be  entitled  to a bonus of up to 25% of your then
current Base Salary by the Company=s  Compensation Committee and ratified by the
Company=s Board of Directors based on the Company  attaining  certain  financial
results(for  information  purposes, a copy of the Company=s Fiscal 1997 Plan has
been  provided to you under  separate  cover).  Such  Bonuses  shall be properly
approved by the Board of Directors or any committee  established  and authorized
to perform such duties by the Board of Directors.

         3. Vacation.  You shall be entitled to all legal holidays recognized by
the Company , and 18 days paid  vacation per annum.  Any unused  vacation may be
accrued or used in accordance with Company policy.

         4. Insurance and Benefits.  You shall be eligible for  participation in
any health, dental, and other group insurance plans which may be established and
maintained  by the Company for all  full-time  employees or which the Company is
required to maintain by law. The Company shall provide you with health insurance
for you and your family providing benefits at least equal to the benefits of the
policies  currently  in place and shall  provide  you with group life  insurance
equal to two times your base salary.  You shall also be entitled to  participate
in any employee  benefit  programs  which the  Company's  Board of Directors may
establish for its key employees, or for its employees generally,  including, but
not limited to, bonuses and stock purchase or option plans. You will be eligible
to participate in the Company's 401(k) Plan.

         5. Stock  Options.  You shall be entitled to receive  stock  options to
purchase up to an  aggregate  of 20,000  shares of common  stock of the Company.
These options shall vest in accordance with the Company=s  normal vesting policy
for stock option grants. A copy of your option grant letter is attached hereto.


                                      A-1








         6. Severance Benefits.

            (a) When  provided for in this  Agreement,  you shall be entitled to
"Severance Benefits." When used in this Agreement, the term "Severance Benefits"
shall mean a total amount equal to (i) fifty  percent (50%) of your then current
annual Base Salary,  plus (ii) your Bonuses earned for the Company's most recent
fiscal year. If the Company's fiscal year is changed, the Bonuses shall be based
upon your bonuses  received  during the Company's  most recent fiscal year.  The
Severance  Benefits  shall be paid via  check  to you in six (6)  equal  monthly
installments  commencing within ten (10) days after the date of your termination
of employment with the Company.

            (b) In addition,  the term  "Severance  Benefits"  shall include the
continuation for you and your family,  during the Severance  Period,  as defined
below,  of all of the other  benefits  which are provided or available to you on
the last day of your  actual  service  with the  Company.  For  purposes of this
Agreement,  the term  "Severance  Period"  means the  period  of six (6)  months
beginning on the Date of Termination.

            (c) The Severance Benefits referred to above will be in addition to,
and not in substitution for, any accrued and unpaid salary,  vacation,  pension,
retirement or other benefits,  unreimbursed  expenses or other payments to which
you may be otherwise entitled.

            (d) In the  event  of  your  death  while  you are  employed  by the
Company,  your then current Base Salary shall  continue to be paid to your legal
representative for a period of 60 days following the date of your death; and for
a period of one (1) years  following  your death,  the Company shall continue to
provide to your spouse at Company cost the health insurance  coverage  described
above.

            (e) You shall not be required to mitigate  the amount of any payment
the Company becomes  obligated to make to you in connection with this Agreement,
by seeking other employment or otherwise.

         7. Change in Control.

            (a) For purposes of this  Agreement,  "Change in Control"  means and
shall be deemed to occur if any of the following occurs:  (i) the acquisition by
an individual,  entity or group,  as defined in Section  13(d)(3) or 14(d)(2) of
the  Securities  Exchange  Act of 1934,  as amended  (the  "Exchange  Act"),  of
beneficial  ownership,  as defined in Rule 13d-3  promulgated under the Exchange
Act, of 50% or more of either (A) the outstanding  shares of common stock, $ .01
par value per share,  of the Company (the "Common  Stock"),  or (B) the combined
voting power of the voting  securities of the Company entitled to vote generally
in the election of directors (the "Voting Securities"); or (ii) individuals who,
on May 1,


                                      A-2








1997,  constituted the Board of Directors of the Company (the "Incumbent Board")
cease for any reason to constitute at least a majority of the Board of Directors
of the  Company;  provided,  however,  that any  individual  becoming a director
subsequent to May 1, 1997,  whose  election,  or nomination  for election by the
Company's  shareholders,  was  approved  by a vote of at least a majority of the
directors then serving and comprising the Incumbent Board shall be considered as
though such individual were a member of the Incumbent Board, but excluding,  for
this purpose, any such individual whose initial assumption of office occurs as a
result of either an actual or  threatened  election  contest  (as such terms are
used in Rule 14a-11 of  Regulation  14A  promulgated  under the Exchange Act) or
other  actual or  threatened  solicitation  of  proxies  or  consents;  or (iii)
approval by the Board of Directors or the  shareholders  of the Company of a (A)
tender  offer to  acquire  any of the  Common  Stock or voting  securities,  (B)
reorganization,  (C) merger or (D)  consolidation,  other than a reorganization,
merger or consolidation  with respect to which all or  substantially  all of the
individuals and entities who were the beneficial  owners,  immediately  prior to
such  reorganization,  merger or  consolidation,  of the Common Stock and voting
securities  beneficially  own,  directly or indirectly,  immediately  after such
reorganization,  merger or consolidation,  more than 80% of the then outstanding
common stock and voting  securities  (entitled to vote generally in the election
of  directors)  of the Company  resulting  from such  reorganization,  merger or
consolidation  in  substantially   the  same  proportions  as  their  respective
ownership, immediately prior to such reorganization, merger or consolidation, of
the Common  Stock and the voting  securities;  or (iv)  Approval by the Board of
Directors or the  shareholders  of the Company of (A) a complete or  substantial
liquidation or dissolution of the Company,  or (B) the sale or other disposition
of all  or  substantially  all  of  the  assets  of  the  Company,  excluding  a
reorganization  of the  Corporation  under  the  corporate  laws of a  state  of
Delaware.

            (b)  In  the  event  of  your  actual   termination   of  employment
contemporaneous  with or  following a Change in  Control,  except (x) because of
your death, (y) by the Company for Cause or Disability (as hereinafter  defined)
or (z) by you other than for Good Reason (as hereinafter defined): (i) you shall
be entitled to receive,  in lieu of the sums  described  in Section 6, an amount
equal to 100% of the Severance  Benefits due and  determined as if payable under
Section 6 above, for each full year or portion thereof you have been employed by
the  Company,  up to a maximum of 299% of the  severance  benefits  mentioned in
Section 6 above, to be paid in accordance with the terms of this Agreement;  and
(ii) the following  additional  provisions  shall apply (which  provisions shall
supersede any other  provisions of the  Agreement,  including but not limited to
Section 2 of the Agreement,  to the extent such provisions are inconsistent with
the following provisions):

                    (1)   Disability.   For  purposes  of  this  Section   7(c),
termination by the Company of your employment  based on "Disability"  shall mean
termination  because of your absence from your duties with the Company on a full
time basis for one hundred  eighty  (180)  consecutive  days as a result of your
incapacity  due to physical or mental  illness,  unless  within thirty (30) days
after Notice of Termination (as  hereinafter  defined) is given to you following
such  absence,  you shall have  returned  to the full time  performance  of your
duties.

                    (2) Good Reason.  Termination by you of your  employment for
"Good Reason" shall mean termination based on:



                                      A-3







                        (A) a  determination  that  there  has  been a  material
adverse  change in your status or  position(s)  as an  executive  officer of the
Company  as in effect  immediately  prior to the Change in  Control,  including,
without  limitation,  a material  adverse change in your status or position as a
result of a  diminution  in your  duties or  responsibilities  (other  than,  if
applicable,  any such change directly  attributable to the fact that the Company
is no  longer  publicly  owned)  or the  assignment  to you  of  any  duties  or
responsibilities which are inconsistent with such status or position(s),  or any
removal  of you from,  or any  failure to  reappoint  or  reelect  you to,  such
position(s)  (except in connection  with the  termination of your employment for
Cause or  Disability  or as a result of your death or by you other than for Good
Reason) and  further  provided  that you have given the  Company  notice of this
material  adverse  change and the  Company has failed to correct  such  material
adverse  change  within a reasonable  period of time (but at least 14 days after
written notice from you);

                        (B) a  reduction  by the  Company  (within  three  years
following  the Change of Control)  in your Base Salary as in effect  immediately
prior to the Change in Control;

                        (C) the  failure  by the  Company  (within  three  years
following the Change of Control) to continue in effect any Plan (as  hereinafter
defined) in which you are  participating at the time of the Change in Control of
the  Company  (or  Plans  providing  you  with at  least  substantially  similar
benefits)  other than as a result of the normal  expiration  of any such Plan in
accordance with its terms as in effect at the time of the Change in Control,  or
the taking of any action,  or the  failure to act,  by the  Company  which would
adversely  affect your continued  participation in any of such Plans on at least
as  favorable a basis to you as is the case on the date of the Change in Control
or which would  materially  reduce your benefits in the future under any of such
Plans or deprive you of any material  benefit  enjoyed by you at the time of the
Change in Control;

                        (D) the failure by the Company to provide and credit you
with the  number  of paid  vacation  days to  which  you are  then  entitled  in
accordance with the Company's  normal  vacation policy as in effect  immediately
prior to the Change in Control;

                        (E)  the  Company's  requiring  you to be  based  at any
office that is greater  than thirty (30) miles from where your office is located
immediately  prior to the Change in Control  except for  required  travel on the
Company's  business  to an extent  substantially  consistent  with the  business
travel  obligations  which you  undertook on behalf of the Company  prior to the
Change in Control;

                        (F) the  failure  by the  Company  to  obtain  from  any
Successor (as hereinafter defined) the assent to this Agreement  contemplated by
Section 7(c)(7) hereof; or

                        (G) any  purported  termination  by the  Company of your
employment which is not effected pursuant to a Notice of Termination  satisfying
the  requirements of Section 7(c)(4) below (and, if applicable,  Section 7(c)(1)
above); and for purposes of this Agreement,  no such purported termination shall
be effective.

                                      A-4







         For purposes of this Agreement, "Plan" shall mean any compensation plan
or any employee benefit plan such as a thrift, pension, profit sharing, medical,
disability,  accident, life insurance plan or a relocation plan or policy or any
other plan, program or policy of the Company intended to benefit employees.

                    (3) [INTENTIONALLY LEFT BLANK]

                    (4) Notice of Termination.  Any purported termination by the
Company or by you following a Change in Control shall be communicated by written
notice to the other  party  hereto  which  indicates  the  specific  termination
provision in this Agreement relied upon (the "Notice of Termination").

                    (5) Date of Termination.  "Date of Termination"  following a
Change in Control  shall mean (A) if your  employment  is to be  terminated  for
Disability, thirty (30) days after Notice of Termination is given (provided that
you shall not have  returned  to the  performance  of your duties on a full-time
basis  during such  thirty (30) day  period),  (B) if your  employment  is to be
terminated  by the Company for any reason other than death or  Disability  or by
you  pursuant to  Sections  7(c)(2)(F)  or 7(c)(7)  hereof or for any other Good
Reason,  the  date  specified  in the  Notice  of  Termination,  or (C) if  your
employment is terminated on account of your death,  the day after your death. In
the case of termination of your employment by the Company for Cause, if you have
not  previously  expressly  agreed in writing to the  termination,  then  within
thirty (30) days after receipt by you of the Notice of Termination  with respect
thereto,  you may  notify  the  Company  that a dispute  exists  concerning  the
Termination, in which event the Date of Termination shall be the date set either
by mutual written agreement of the parties or by arbitration as described in '17
of the Agreement.

                    (6)  Compensation  Upon  Termination  or During  Disability;
Other Agreements.

                        (A) During any period  following  a Change in Control of
the Company that you fail to perform your duties as a result of  incapacity  due
to physical or mental illness, you shall continue to receive your Base Salary at
the rate then in effect and any benefits or awards under any Plan shall continue
to accrue during such period,  to the extent not  inconsistent  with such Plans,
until and unless your  employment  is  terminated  pursuant to and in accordance
with this  Section  7(c).  Thereafter,  your  benefits  shall be  determined  in
accordance with the Plans then in effect.

                        (B) If your employment is terminated for Cause following
a Change in  Control  of the  Company,  the  Company  shall pay to you your Base
Salary  through the Date of  Termination at the rate in effect just prior to the
time a Notice of  Termination  is given plus any  benefits or awards  (including
both the cash and stock  components)  which  pursuant  to the terms of any Plans
have been  earned or become  payable,  but which  have not yet been paid to you.
Thereupon,  the  Company  shall  have no further  obligations  to you under this
Agreement.

                                      A-5






                    (7) Successors, Binding Agreement.

                        (A) The Company will seek,  by written  request at least
five (5)  business  days  prior to the time a Person  becomes  a  Successor  (as
hereinafter  defined),  to have such Person,  by agreement in form and substance
satisfactory  to you,  assent to the  fulfillment  of the Company's  obligations
under this Agreement. Failure of such Person to furnish such assent by the later
of (i) three (3) business days prior to the time such Person becomes a Successor
or (ii) two (2) business days after such Person receives a written request to so
assent shall constitute Good Reason for termination by you of your employment if
a Change in Control of the Company occurs or has occurred.  For purposes of this
Section 7 of Exhibit A,  "Successor"  shall mean any person that succeeds to, or
has the practical ability to control, the Company's business directly, by merger
or  consolidation,  or  indirectly,  by  purchase  of the  Company's  securities
eligible to vote for the election of directors, or otherwise.

                        (B) This Agreement  shall inure to the benefit of and be
enforceable by your personal legal representatives,  executors,  administrators,
successors, heirs, distributees,  devisees and legatees. If you should die while
any amount would still be payable to you hereunder if you had continued to live,
all such amounts,  unless otherwise provided herein, shall be paid in accordance
with the terms of this Agreement to your devisee,  legatee or other designee or,
if no such designee exists, to your estate.

                        (C) For purposes of this Section 7, the "Company"  shall
include any  subsidiaries  of the Company and any  corporation  or other  entity
which  is  the  surviving  or  continuing  entity  in  respect  of  any  merger,
consolidation  or form of business  combination  in which the Company  ceases to
exist;  provided,  however,  for  purposes  of  determining  whether a Change in
Control has occurred  herein,  the term "Company" shall refer to Applied Science
and Technology, Inc. or its Successor(s).

                    (8) Fees and Expenses; Mitigation.

                        (A) The Company shall reimburse you, on a current basis,
for all reasonable legal fees and related expenses incurred by you in connection
with the  Agreement  following  a Change in  Control of the  Company,  including
without  limitation,  (i) all  such  fees  and  expenses,  if any,  incurred  in
contesting or disputing any  termination of your employment or (ii) your seeking
to obtain or enforce any right or benefit  provided by this  Agreement,  in each
case,  regardless of whether or not your claim is upheld by a court of competent
jurisdiction; provided, however, you shall be required to repay any such amounts
to the  Company to the  extent  that a court  issues a final and  non-appealable
order  setting  forth  the  determination  that  the  position  taken by you was
frivolous or advanced by you in bad faith.

                                      A-6






                        (B) You shall not be required to mitigate  the amount of
any payment the Company becomes obligated to make to you in connection with this
Agreement, by seeking other employment or otherwise.

                    (9)  Taxes.  All  payments  to be  made  to you  under  this
Agreement will be subject to required  withholding  of federal,  state and local
income and employment taxes.

            (d)  Notwithstanding  any other provision of this Agreement,  in the
event that any payment or benefit  received or to be received by you as a result
of or in connection with a Change in Control,  whether  pursuant to the terms of
this Agreement or any other plan, arrangement or agreement with the Company (all
such payment and benefits being  hereinafter  called the "Total Payments") would
subject you to the excise tax (the "Excise  Tax")  imposed under Section 4999 of
the Internal Revenue Code of 1986, as amended (the "Code"),  then, to the extent
necessary to eliminate any such  imposition of the Excise Tax (after taking into
account any reduction in the Total Payments in accordance with the provisions of
any other plan,  arrangement or agreement,  if any), (a) any non-cash  severance
payments  otherwise  payable to you shall  first be reduced  (if  necessary,  to
zero), and (b) any cash severance payment otherwise payable to you shall next be
reduced. For purposes of the immediately  preceding sentence,  (i) no portion of
the Total Payments the receipt or enjoyment of which you shall have  effectively
waived in  writing  shall be taken  into  account,  (ii) no portion of the Total
Payment    shall   be   taken   into   account   which   in   the   opinion   of
nationally-recognized  certified  public  accountants  (in each case as mutually
selected by you and the  Company)  does not  constitute  a  "parachute  payment"
within the meaning of Section 280G of the Code,  including,  without limitation,
by reason of Section  280G(b)(2) or (b)(4)(A) of the Code, (iii) any payments to
you shall be reduced  only to the extent  necessary  so that the Total  Payments
[other  than  those  referred  to in  clauses  (i) and  (ii)] in their  entirety
constitute  reasonable  compensation for services  actually  rendered within the
meaning  of  section  280G(4)(B)  of the Code or are  otherwise  not  subject to
disallowance as deductions, in the opinion of the tax counsel or the accountants
referred to in clause (ii);  and (iv) the value of any  non-cash  benefit or any
deferred  payment or benefit  included in the Total Payments shall be determined
by such  accountants in accordance with the  requirements of section  280G(d)(3)
and (4) of the  Code  (and  such  determination  shall be  reviewed  by such tax
counsel).

         8. Expenses. The Company shall reimburse you for all usual and ordinary
business expenses incurred by you in the scope of your employment hereunder.

                      [THIS SPACE INTENTIONALLY LEFT BLANK]






                                      A-7








                                      
                                                                      EXHIBIT B



                    OUTSIDE EMPLOYMENTS AND DIRECTORSHIPS OF

                                 MICHAEL DeLUCA



                                      None









                                      B-1









                                     
                                                                       EXHIBIT C


--------------------------------------------------------------------------------


                PROPRIETARY INFORMATION AND INVENTIONS AGREEMENT


To:      Applied Science and Technology, Inc.
         35 Cabot Road
         Woburn, Massachusetts  01801

                                                             As of May 1, 1997

         The  undersigned,  in  consideration  of  and  as  a  condition  of  my
employment  or continued  employment  by you and/or by companies  which you own,
control,  or are affiliated with or their successors in business  (collectively,
the "Company"), hereby agrees as follows:

         1. Confidentiality. I agree to keep confidential, except as the Company
may otherwise consent in writing,  and, except for the Company's benefit, not to
disclose  or make any use of at any  time  either  during  or  subsequent  to my
employment, any Inventions (as hereinafter defined), trade secrets, confidential
information,  knowledge,  data or other  information of the Company  relating to
products,  processes,  know-how,  designs,  formulas, test data, customer lists,
business plans,  marketing plans and strategies,  pricing  strategies,  or other
subject  matter  pertaining  to  any  business  of  the  Company  or  any of its
affiliates,  which I may produce, obtain, or otherwise acquire during the course
of my  employment,  except as herein  provided.  I further agree not to deliver,
reproduce or in any way allow any such trade secrets,  confidential information,
knowledge, data or other information,  or any documentation relating thereto, to
be  delivered  to or used by any third  parties  without  specific  direction or
consent of a duly authorized representative of the Company.

          2. Conflicting  Employment;  Return of Confidential  Material. I agree
that  during  my  employment  with the  Company  I will not  engage in any other
employment, occupation, consulting or other activity relating to the business in
which  the  Company  is now or may  hereafter  become  engaged,  or which  would
otherwise  conflict  with  my  obligations  to  the  Company.  In the  event  my
employment  with the Company  terminates for any reason  whatsoever,  I agree to
promptly surrender and deliver to the Company all records, materials, equipment,
drawings,  documents and data of which I may obtain or produce during the course
of my  employment,  and I will not take with me any  description  containing  or
pertaining  to any  confidential  information,  knowledge or data of the Company
which I may produce or obtain during the course of my employment.



                                     C-1









         3. Assignment of Inventions.

            3.1 I hereby  acknowledge and agree that the Company is the owner of
all Inventions.  In order to protect the Company's rights to such Inventions, by
executing  this  Agreement  I hereby  irrevocably  assign to the  Company all my
right, title and interest in and to all Inventions to the Company.

            3.2 For  purposes  of this  Agreement,  "Inventions"  shall mean all
discoveries,  processes, designs, technologies,  devices, or improvements in any
of the foregoing or other ideas,  whether or not  patentable  and whether or not
reduced to practice,  made or  conceived  by me (whether  solely or jointly with
others) during the period of my employment  with the Company which relate in any
manner to the actual or demonstrably anticipated business, work, or research and
development of the Company, or result from or are suggested by any task assigned
to me or any work performed by me for or on behalf of the Company.

            3.3  Any  discovery,   process,  design,   technology,   device,  or
improvement  in any of the foregoing or other ideas,  whether or not  patentable
and whether or not reduced to practice,  made or conceived by me (whether solely
or jointly with others) which I develop entirely on my own time not using any of
the  Company's  equipment,  supplies,  facilities,  or trade secret  information
("Personal  Invention") is excluded from this  Agreement  provided such Personal
Invention  (a)  does  not  relate  to the  actual  or  demonstrably  anticipated
business,  research and  development  of the  Company,  and (b) does not result,
directly or indirectly, from any work performed by me for the Company.

         4.  Disclosure  of  Inventions.  I agree  that in  connection  with any
Invention,  I will promptly disclose such Invention to my immediate  superior at
the  Company in order to permit the Company to enforce  its  property  rights to
such  Invention  in  accordance  with this  Agreement.  My  disclosure  shall be
received in confidence by the Company.

         5. Patents and Copyrights; Execution of Documents.

            5.1 Upon  request,  I agree to assist the Company or its nominee (at
its  expense)  during  and at any  time  subsequent  to my  employment  in every
reasonable  way to  obtain  for its  own  benefit  patents  and  copyrights  for
Inventions in any and all countries.  Such patents and  copyrights  shall be and
remain the sole and exclusive property of the Company or its nominee. I agree to
perform  such lawful acts as the Company  deems to be  necessary  to allow it to
exercise all right, title and interest in and to such patents and copyrights.

            5.2  In  connection  with  this  Agreement,   I  agree  to  execute,
acknowledge  and deliver to the Company or its nominee  upon  request and at its
expense all  documents,  including  assignments  of title,  patent or  copyright
applications,  assignments  of such  applications,  assignments  of  patents  or
copyrights upon issuance, as the Company may determine necessary or desirable to


                                      C-2







protect the Company's or its nominee's interest in Inventions,  and/or to use in
obtaining  patents  or  copyrights  in any and all  countries  and to vest title
thereto in the Company or its nominee to any of the foregoing.

         6. Maintenance of  Records.  I agree to keep and maintain  adequate and
current  written  records  of all  Inventions  made by me (in the form of notes,
sketches,  drawings and other records as may be specified by the Company), which
records shall be available to and remain the sole property of the Company at all
times.

         7. Prior Inventions.  It is understood that all Personal Inventions, if
any, whether patented or unpatented,  which I made prior to my employment by the
Company, are excluded from this Agreement. To preclude any possible uncertainty,
I have set forth on  Schedule  A attached  hereto a  complete  list of all of my
prior  Personal  Inventions,   including  numbers  of  all  patents  and  patent
applications and a brief description of all unpatented Personal Inventions which
are not the property of a previous  employer.  I represent and covenant that the
list is  complete  and that,  if no items are on the list,  I have no such prior
Personal Inventions.  I agree to notify the Company in writing before I make any
disclosure  or  perform  any work on  behalf of the  Company  which  appears  to
threaten or conflict with proprietary rights I claim in any Personal  Invention.
In the event of my  failure  to give such  notice,  I agree  that I will make no
claim against the Company with respect to any such Personal Invention.

         8. Other Obligations.  I acknowledge that the Company from time to time
may have agreements  with other persons or with the U.S.  Government or agencies
thereof,  which impose  obligations  or  restrictions  on the Company  regarding
Inventions   made  during  the  course  of  work  thereunder  or  regarding  the
confidential  nature of such work.  I agree to be bound by all such  obligations
and  restrictions  and to take all action  necessary to discharge  the Company's
obligations.

         9. Trade Secrets of Others.  I represent that my performance of all the
terms of this  Agreement and as an employee of the Company does not and will not
breach any agreement to keep confidential proprietary information,  knowledge or
data acquired by me in  confidence  or in trust prior to my employment  with the
Company,  and I will not disclose to the Company,  or induce the Company to use,
any  confidential  or  proprietary  information  or  material  belonging  to any
previous  employer  or others.  I agree not to enter into any  agreement  either
written or oral in conflict herewith.

         10.  Modification.  I agree that any subsequent change or changes in my
employment duties,  salary or compensation or, if applicable,  in any Employment
Agreement  between the Company and me, shall not affect the validity or scope of
this Agreement.

         11.  Successors and Assigns.  This  Agreement  shall be binding upon my
heirs,  executors,  administrators or other legal representatives and is for the
benefit of the Company, its successors and assigns.


                                      C-3









         12.  Interpretation.  IT IS THE INTENT OF THE PARTIES  THAT in case any
one or more of the provisions contained in this Agreement shall, for any reason,
be held to be invalid, illegal or unenforceable in any respect, such invalidity,
illegality  or  unenforceability  shall not affect the other  provisions of this
Agreement,  and this Agreement shall be construed as if such invalid, illegal or
unenforceable  provision had never been contained  herein.  MOREOVER,  IT IS THE
INTENT OF THE PARTIES THAT in case any one or more of the  provisions  contained
in this  Agreement  shall for any reason be held to be  excessively  broad as to
duration,  geographical  scope,  activity or subject,  such  provision  shall be
construed by limiting and reducing it in  accordance  with a judgment of a court
of competent jurisdiction, so as to be enforceable to the extent compatible with
applicable law.

         13.  Waivers.  If either party should waive any breach of any provision
of this  Agreement,  he or it shall not  thereby  be deemed to have  waived  any
preceding  or  succeeding  breach  of the same or any  other  provision  of this
Agreement.

         14.  Complete  Agreement,  Amendments.  I  acknowledge  receipt of this
Agreement,  and agree that with respect to the subject  matter  thereof it is my
entire  agreement  with the Company,  superseding  any previous  oral or written
communications, representations,  understandings, or agreements with the Company
or any officer or  representative  thereof.  Any amendment to this  Agreement or
waiver  by  either  party of any  right  hereunder  shall be  effective  only if
evidenced by a written  instrument  executed by the parties hereto,  and, in the
case of the  Company,  upon  written  authorization  of the  Company's  Board of
Directors.

         15.  Headings.  The  headings of the  sections  hereof are inserted for
convenience  only and shall not be deemed to  constitute  a part  hereof  nor to
affect the meaning thereof.

         16.  Counterparts.  This  Agreement may be signed in two  counterparts,
each of which  shall be  deemed an  original  and both of which  shall  together
constitute one agreement.

         17. Governing Law. This Agreement shall be governed and construed under
Massachusetts law.

         18 Employment  Status.  Nothing in this  Agreement  shall affect in any
manner  whatsoever the right or power of the Company to terminate the employment
of the Employee.

                                               EMPLOYEE


                                               ---------------------------------
                                               Michael DeLuca

Accepted and Agreed:
APPLIED SCIENCE AND TECHNOLOGY,  INC.


By:
   ------------------------------------------
      Dr. Richard S. Post, President


                                      C-4







                                                                      SCHEDULE A



                            LIST OF PRIOR INVENTIONS
                                OF MICHAEL DeLUCA



                                                         Identifying Number or
        Title                Date                          Brief Description
        -----                ----                          -----------------

                                      NONE



                                      C-5