Ex 4.1


ZYGO CORPORATION


EMPLOYEE STOCK PURCHASE PLAN


          1.
Purpose. The purpose of the Zygo Corporation Employee Stock Purchase
Plan is to provide Eligible Employees of the Company and its Subsidiaries with
a means to acquire shares of Common Stock through payroll deductions. The Plan
is intended to qualify as an “employee stock purchase plan” under Section 423
of the Code and shall be interpreted and construed accordingly.


          2.
Definitions. For purposes of the Plan, the following terms have the
following meanings:


                    “Account” shall mean the bookkeeping
account established in the name of each Participant to reflect the payroll
deductions made on behalf of the Participant.


                    “Board” shall mean the Board of Directors
of the Company.


                    “Code” shall mean the Internal Revenue Code
of 1986, as amended.


                    “Committee” shall mean the committee
appointed to administer the Plan in accordance with Section 4 or, if no such
committee is duly constituted or appointed, the Board.


                    “Common Stock” shall mean the Company’s
common stock, par value, $0.10.


                    “Company” shall mean Zygo Corporation, a
Delaware corporation, and any successor thereto.


                    “Compensation” shall mean the base
compensation paid by the Company or a Subsidiary to a Participant which is
required to be reported as wages on the Participant’s Form W-2, including such
additional amounts which are not includible in gross income by reason of
Sections 125, 402(e)(3) or 402(h)(1)(B) of the Code, and excluding any bonuses,
overtime pay, severance, sick leave, expense and relocation allowances, gains
from the exercise of stock options and other irregular payments (except commissions).


                    “Employee” shall mean any person on the
active employment payroll of the Company or any of its Subsidiaries. Any person
classified by the Company or any of its Subsidiaries at the time services are
provided as an independent contractor or consultant shall not be eligible to
participate in the Plan during the period which he or she is so classified even
if later retroactively reclassified as an Employee during all or any part of
such period pursuant to applicable law or otherwise.


                    “Eligible Employee” shall mean, with
respect to an Offering Period, any Employee on the Enrollment Date who
satisfies each of the following criteria:


                    the
Employee does not immediately after the grant, directly or indirectly, own





stock (as defined by the Code) and/or hold outstanding
options to purchase stock possessing five percent (5%) or more of the total
combined voting power or value of all classes of stock of the Company or a
“parent corporation” or Subsidiary of the Company;


                    the
Employee’s customary employment is for twenty (20) hours or more per week or
such lesser number of hours established by the Committee on a uniform and
nondiscriminatory basis; and


                    the
Employee customarily works a minimum of five (5) months per year, or such
lesser number of months established by the Committee on a uniform and
nondiscriminatory basis.


If the Committee permits any Eligible Employee of a
Subsidiary to participate in the Plan during an Offering Period, then all
Eligible Employees of that Subsidiary shall also be permitted to participate in
the Plan during such Offering Period.


                    “Enrollment Date” shall mean the first day
of an Offering Period.


                    “Exercise Date” shall mean the last day of
an Offering Period.


                    “Fair Market Value” for purposes of the
Plan, unless otherwise required by the Code, shall mean, as of any date, the
closing sale price per share of Common Stock as published by the principal
national securities exchange on which the Common Stock is traded on such date
or, if there is no sale of Common Stock on such date, the average of the bid
and asked prices on such exchange at the close of trading on such date, or if
shares of the Common Stock are not listed on a national securities exchange on
such date, the last reported trading price or, if none, the average of the bid
and asked prices in the over-the-counter market at the close of trading on such
date. If there is no such reported price for the Common Stock for the date in
question due to the applicable stock market not being open for trading, then
such price on the last preceding date for which such price exists shall be
determinative of Fair Market Value.


                    “Offering Period” shall mean each period
designated as such by the Committee, subject to compliance with Section 423 of
the Code; provided, however, that the duration of each Offering Period will be
no less than one month and no more than 27 months. The number of Offering
Periods in any calendar year may not exceed twelve.


                    “Participant” shall mean any Eligible
Employee for whom an Account is maintained under the Plan.


                    “Purchase Price” shall mean, subject to
adjustment pursuant to Section 10 hereof, ninety percent (90%) of the lesser of the Fair Market Value of a
share of Common Stock on (i) the Enrollment Date or (ii) the Exercise Date.


                    “Plan” shall mean this Zygo Corporation
Employee Stock Purchase Plan, as amended from time to time.


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                    “Subsidiary” shall mean any “subsidiary
corporation” of the Company (within the meaning of Section 424(f) of the Code)
that is designated by the Committee as an eligible Subsidiary under the Plan
from time to time.


          3.
Available Shares. Subject to adjustment as provided in Section 10, the
maximum number of shares of Common Stock that may be sold under the Plan shall
not exceed 1,000,000 shares. Such shares may be either authorized and unissued
or held by the Company in its treasury. The Committee may cause the Company to
purchase previously issued and outstanding shares of Common Stock in order to
enable the Company to satisfy its obligations hereunder. Subject to the annual limitation described in Section
5 and to adjustment pursuant to Section 10 or as otherwise determined by
the Committee prior to the commencement of any Offering Period, the maximum
number of shares of Common Stock a Participant may purchase during any Offering
Period shall not exceed 2,000 shares.


          4.
Administration. The Plan shall be administered by the Company’s
Compensation Committee or such other committee appointed by the Board from time
to time. Subject to the provisions of the Plan, the Committee, acting in its
sole and absolute discretion, shall have full power and authority to interpret
the provisions of the Plan, to change the time covered by an Offering Period,
to supervise the administration of the Plan, and to take such other action as
may be necessary or desirable in order to carry out the provisions of the Plan.
A majority of the members of the Committee shall constitute a quorum. The
Committee may act by the vote of a majority of its members present at a meeting
at which there is a quorum or by written consent. The decision of the
Committee, including questions of construction, interpretation and
administration, shall be final, binding and conclusive on all persons. The
Company shall indemnify and hold harmless each member of the Committee and any
employee or director of the Company or of a Subsidiary who provides assistance
or performs services in connection with the administration or interpretation of
the Plan against any loss, cost, liability (including any sum paid in
settlement of a claim with the approval of the Board), damage and expense
(including legal and other expenses incident thereto) arising out of or
incurred in connection with the Plan, unless and except to the extent
attributable to such person’s fraud or willful misconduct.


          5.
Eligibility and Enrollment. An Eligible Employee shall become a
Participant on the first Enrollment Date occurring on or after his or her
satisfaction of the Plan’s eligibility requirements and completion of a Plan
enrollment form authorizing payroll deductions. Such enrollment form must be
filed with the Company prior to the applicable Offering Period and during the
enrollment period established by the Company. Payroll deductions for a
Participant shall commence with the first payroll and shall end with the last
payroll in the Offering Period to which such authorization is applicable,
unless sooner terminated by the Participant in accordance with the provisions
hereof. Notwithstanding any provisions of the Plan to the contrary, to the
extent required by applicable law, no Participant may be granted the right to
purchase Common Stock under the Plan if and to the extent that the
Participant’s right to purchase stock under all employee stock purchase plans
(within the meaning of Section 423 of the Code) of the Company or a Subsidiary
would accrue at a rate which exceeds $25,000 in Fair Market Value (determined
at the time of grant) in accordance with the Code for each calendar year in
which such right is outstanding.


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          6.
Payroll Deduction. At the time a Participant enrolls in the Plan, he or
she must elect the amount to be deducted from each paycheck during the Offering
Period(s) covered by the election, provided that (i) unless otherwise
determined by the Committee with respect to future Offering Periods, no more
than ten percent (10%) of a Participant’s Compensation may be withheld under
the Plan on any pay date, and (ii) the Committee, acting in its discretion and
in a uniform and nondiscriminatory manner, may establish a minimum required amount
or percentage of Compensation which must be withheld during an Offering Period.
All payroll deductions made for a Participant shall be credited to the
Participant’s Account. Interest shall not accrue on any amounts credited to a
Participant’s Account. The rate of a Participant’s contribution, once
established, shall remain in effect for all subsequent Offering Periods unless
changed by the Participant in writing at such time and in such manner as the
Committee may prescribe.


          7.
Purchase of Shares. On each Exercise Date, the amount credited to a
Participant’s Account shall be used to purchase a whole number of shares of
Common Stock, the number of which will be determined by dividing the amount
credited to the Participant’s Account by the Purchase Price per share. Any
amount remaining in the Participant’s Account shall be credited to the
Participant’s Account as of the beginning of the next Offering Period. If the
total number of shares of Common Stock to be purchased as of an Exercise Date,
when aggregated with shares of Common Stock previously purchased under the
Plan, exceeds the number of shares then authorized under the Plan, a pro-rata
allocation of the available shares shall be made among the Participants based
upon the amounts in their respective Accounts as of the Exercise Date.


          8.
Discontinuance or Withdrawal; Withholding Changes.


                    8.1
Discontinuance or Withdrawal. At any time during an Offering Period, a
Participant may notify the Company that he or she wishes to discontinue
contributions under the Plan. This notice shall be in writing and shall become
effective as soon as practicable following its receipt by the Company. A
Participant may elect to withdraw all, but not less than all, of the amount of
his or her Account at any time during an Offering Period, except on the
Exercise Date with respect to that Offering Period. If a withdrawal is made
during an Offering Period, no further contributions shall be permitted during
that Offering Period by the withdrawing Participant.


                    8.2
Withholding Changes. At any time during an Offering Period, a
Participant may increase or decrease the rate of his or her payroll deductions
by completing and filing with the Company a new enrollment form authorizing a
change in payroll deduction rate. The Committee may, in its discretion, limit
the number of payroll deduction rate changes during any Offering Period. The
change in rate shall be effective as soon as practicable following the
Company’s receipt of the new enrollment form.


                    8.3
Termination of Employment. Any Participant whose employment with the
Company and its Subsidiaries is terminated for any reason before an Exercise
Date shall thereupon cease being a Participant. The total amount credited to
the Participant’s Account during the Offering Period shall be returned to the
Participant or, in the case of a deceased Participant, to the Participant’s
beneficiary, as soon as practicable after the Participant’s


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termination of employment.


          9.
Rights as a Stockholder. No shares of Common Stock shall be issued under
the Plan until full payment therefor has been made. A Participant shall have no
rights as a stockholder with respect to any shares until the date a stock
certificate (or its equivalent) for such shares are issued to him or her.
Except as otherwise specifically provided herein, no adjustments shall be made
for dividends or distributions of other rights for which the record date is
prior to the date such stock certificate (or its equivalent) is issued.


          10.
Capital Changes; Reorganization; Sale.


                    10.1
Adjustments upon Changes in Capitalization. The aggregate number and
class of shares of Common Stock which may be sold under the Plan and purchased
by a Participant, as well as the number and class of shares of Common Stock and
the price per share covered by each right outstanding under the Plan which has
not yet been exercised, shall be adjusted proportionately or as otherwise
appropriate to reflect any increase or decrease in the number of issued shares
of Common Stock resulting from a split-up or consolidation of shares or any
like capital adjustment, or the payment of a stock dividend, and/or to reflect
a change in the character or class of shares covered by the Plan arising from a
readjustment or recapitalization.


                    10.2
Cash, Stock or Other Property for Stock. Except as otherwise provided in
this Section, in the event of an Exchange Transaction (as defined below), each
Participant shall be permitted to purchase Common Stock with the balance of his
or her Account immediately prior to such Exchange Transaction, and any amount
credited to a Participant’s Account which is not used to purchase Common Stock
before the Exchange Transaction shall be distributed to the Participant.
Notwithstanding the preceding sentence, (i) if, as part of the Exchange
Transaction, the stockholders of the Company receive capital stock of another
corporation (“Exchange Stock”) in exchange for their shares of Common Stock
(whether or not such Exchange Stock is the sole consideration), and if the
Board, in its sole discretion, so directs, then the rights of all Participants
to purchase shares of Common Stock shall be converted into rights to purchase
shares of Exchange Stock on an economically equivalent basis; and (ii) the
Board, acting in its discretion, may suspend operation of the Plan as of any
date that occurs after a contract is made which, if consummated, would result
in an Exchange Transaction and before the Exchange Transaction is consummated.


                    10.3
Definition of Exchange Transaction. For purposes hereof, the term
“Exchange Transaction” shall mean a merger (other than a merger of the Company
in which the holders of Common Stock immediately prior to the merger have the
same proportionate ownership of Common Stock in the surviving corporation
immediately after the merger), consolidation, acquisition of property or stock,
separation, reorganization (other than a mere reincorporation or the creation
of a holding company), liquidation of the Company or any other similar
transaction or event so designated by the Board in its sole discretion, as a
result of which the stockholders of the Company receive cash, stock or other
property in exchange for or in connection with their shares of Common Stock.


                    10.4
Determination of Committee to be Final. All adjustments under this


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Section 10 shall be made by the Committee, and its
determination as to what adjustments shall be made, and the extent thereof,
shall be final, binding and conclusive.


          11.
Amendment and Termination. The Board may amend or terminate the Plan at
any time; provided, however, that, except as otherwise provided in Section 10
hereof, any amendment which increases the aggregate number of shares of Common
Stock which may be issued under the Plan, modifies the corporations or class of
corporations whose employees are offered options under the Plan or otherwise
requires stockholder approval under applicable law shall be subject to the
approval of the Company’s stockholders.


          12.
Transferability. The rights of a Participant to purchase Common Stock
under the Plan are not assignable or transferable and may only be exercised
during the Participant’s lifetime by the Participant. A Participant may file a
written designation of a beneficiary who is to receive the amount credited to
the Participant’s Account in the event of the Participant’s death during an
Offering Period. A Participant’s beneficiary designation may be changed by the
Participant at any time by written notice. In the event of the death of a
Participant and in the absence of a validly designated beneficiary who is
living at the time of the Participant’s death, the Participant’s estate shall
be deemed to be his or her designated beneficiary.


          13.
No Rights Conferred. Nothing contained in the Plan shall be deemed to
give any individual any right to be retained in the employ of the Company and
its Subsidiaries or to interfere with the right of the Company and its
Subsidiaries to discharge him or her at any time.


          14.
Use of Funds. All payroll deductions received or held by the Company
under the Plan may be used by the Company for any corporate purpose, and the
Company shall not be obligated to segregate such payroll deductions.


          15.
Legal Requirements. The Committee may impose such other conditions with
respect to the purchase of Common Stock hereunder, including, without
limitation, any conditions relating to the application of federal or state
securities laws and/or any exchange or listing requirements as it may deem
necessary or advisable.


          16.
Governing Law. The Plan shall be governed by the laws of the State of
Delaware, without regard to its principles of conflicts of law.


          17.
Decisions and Determinations. Any decision or determination made by the
Board pursuant to the provisions hereof and, except to the extent rights or
powers under the Plan are reserved specifically to the discretion of the Board,
all decisions and determinations of the Committee are final, binding and
conclusive.


          18.
Effective Date. The Plan shall become effective as of the date of its
adoption by the Board, subject to approval by the Company’s stockholders within
twelve (12) months thereafter.


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