<?xml version="1.0"?><ownershipDocument>    <schemaVersion>X0101</schemaVersion><documentType>4</documentType><periodOfReport>2003-05-08</periodOfReport><notSubjectToSection16>0</notSubjectToSection16><issuer><issuerCik>0000906193</issuerCik>        <issuerName>KEY TECHNOLOGY INC</issuerName><issuerTradingSymbol>KTEC</issuerTradingSymbol></issuer><reportingOwner><reportingOwnerId><rptOwnerCik>0001228913</rptOwnerCik>            <rptOwnerName>BEST PHYLLIS C</rptOwnerName>        </reportingOwnerId>        <reportingOwnerAddress>            <rptOwnerStreet1>  </rptOwnerStreet1>            <rptOwnerStreet2>  </rptOwnerStreet2>            <rptOwnerCity>  </rptOwnerCity>            <rptOwnerState>  </rptOwnerState>            <rptOwnerZipCode>  </rptOwnerZipCode>        </reportingOwnerAddress><reportingOwnerRelationship><isDirector>0</isDirector><isOfficer>1</isOfficer><isTenPercentOwner>0</isTenPercentOwner><isOther>0</isOther><officerTitle>Chief Financial Officer</officerTitle><otherText></otherText></reportingOwnerRelationship></reportingOwner><derivativeSecurity><securityTitle><value>Employee Stock Option (right to buy)</value></securityTitle><conversionOrExercisePrice><value>9.70</value></conversionOrExercisePrice><transactionDate><value>2003-05-08</value></transactionDate><deemedExecutionDate><value>2003-05-08</value></deemedExecutionDate><transactionCoding><transactionFormType>4</transactionFormType><transactionCode>A</transactionCode><equitySwapInvolved>false</equitySwapInvolved><footnoteId id="F1"/></transactionCoding><transactionTimeliness><value></value></transactionTimeliness><transactionAmounts><transactionShares><value>5000</value></transactionShares><transactionValue><value>9.70</value></transactionValue><transactionAcquiredDisposedCode><value>A</value></transactionAcquiredDisposedCode></transactionAmounts><exerciseDate><value>2004-05-08</value><footnoteId id="F2"/></exerciseDate><expirationDate><value>2008-05-08</value></expirationDate><underlyingSecurity><underlyingSecurityTitle><value>Common Stock</value></underlyingSecurityTitle><underlyingSecurityShares><value>5000</value></underlyingSecurityShares></underlyingSecurity><postTransactionAmounts><sharesOwnedFollowingTransaction><value>5000</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership></ownershipNature></derivativeSecurity><footnotes><footnote id="F1">Granted pursuant to the Restated Employees' Stock Option Plan, a Rule 16b-3 plan.</footnote><footnote id="F2">25 percent of such options will become exercisable on May 8, 2004, 2005, 2006 and 2007, respectively.</footnote></footnotes><ownerSignature><signatureName>Phyllis C. Best</signatureName><signatureDate>2003-05-08</signatureDate></ownerSignature></ownershipDocument>

