The CECOM Center for Night Vision and Electro-OpticsOPTOELECTRONIC WORKSHOPS00OPTO-ELECTRONICS IN IIl-V SEMICONDUCTORS:MATERIALS AND DEVICESMay 3, 1988sponsored jointly byARO-URI Center for Opto-Electronic Systems ResearchThe Institute of Optics, University of Rochester
*UNCLASSIFIEDSECURITY CLASSIFICATIODOF THIS PAGEREPORT DOCUMENTATION PAGEIs. REPORT SECURITY CLASSIFICATION1b. RESTRICTIVE MARKINdS2&. SECURITY CLASSIFICATION AUTHIORITY3. DISTR11UTIO)iIAVAjLABIuTy OF REPORT2b. DECLASE FCATION/OOWWJ6RADING SCHEDULEApproved for public release;distribution unlimited.4. PERFORMING ORGANIZATION REPORT NUMBER(S)5.MONITORING ORGANIZATION REPORT KUMER(S)6a. NAME OF PERFORMING OPCGANIZATION7a. NAME OF MONITORING ORGANIZATION6b. OFFICE SYMBOL(If applicable)University of RochesterU.S6c. ADDRESS (Oty. State, a&d ZIP Code)ryRserhOfc7b. ADDRESS (Cty, State, and ZIP Code)The Insitute of OpticsRochester, NY 14627P. 0. Box 12211Research Triangle Park, NCBe. NAME OF FUNDISPONSORINGORGANIZATION6b. OFFICE SYMBOL(f ipplcbe)O9. PROCUREMENT INSTRUMENT IDENTIFICATION NUMBERU. S. Army Research Office19403-?Sc. ADDRESS (City, State, and ZIP Code)27709-2211k6710. SOURCE OF FUNDING NUMBERSP. 0. Box 12211PROGRAMELEMENT NO.27709-2211Research Triangle Park, NCPROJECTNO.KUNO.IONSNN.INO.NOr11. TITLE (Includ SeCurityC alafako)Optoelectronic Workshop III:12. PERSONAL. AUTHOR(S)Gr13a. TYPE OF REPORTOpto-Electronics in IIl-V Semiconductors:and DevicesMaterialsik13ab. TIME COVERED14. DATE OF REPORT (YearMontADayS1.PAGE COUNTFROMTOMay 3, 19881'16. SUPPLEMENTARY NOTATION The view, opinions and/or findings contained in thisreport are thoseITechnicalof hr) auhan17.FIELDIshulda n fficial Deartuent of the Army position,1S. SUBJECT TERMS (Condinu on rewi Nfneceaavy end ilentify by block number)nbef"AcosCOSATI CODESGROUPSUB-GROUWorkshop:III-V Semiconductors:Materials and Devices'9. ABSTRACT (Contu an reve'se If necenaiy and Ident by block number)'T his workshop on pto-Electronics in Ill-V Semiconductors: Materials and Deviceskrepresents the third of a series of intensive academic/ government interactions inthe field of advanced electro-optics, as part of the Army sponsored UniversityResearch initiative., By documenting the associated technology status and dialogueit is hoped that thi\,baseline will serve all interested parties towards providing asolution to high priority Army requirements. Responsible for program andprogram execution areDr. Nicholas George, University of Rochester (ARO-URI) andDr. Rudy Buser, NVEOC.* A--'It f\Lo20. DISTRIBUTION/ AVAELAIUY OF ABSTRACTO3UNCLASSIFIEDJNLIMTED - 0 SAME AS RPT.22a. NAME OF RESPONSIBLE INDIVIDUALNicholas GeorgeDD FORM 1473, B4 MAR121. ABSTRACT SECURITY CLASSIFICATIONC) OTIC USERSUnclassifiedI22b. TELEPH4ONE (include Arts Code)I716-275-241783 APR edition may be used until eidtauted.'AX other editions are obsoWee---122c. OFFICE SYMBOLSECURITY gLSSFICATION OF TIS PAGEUNCLASSIFIED
OPTOELECTRONIC WORKSHOPONOPTO-ELECTRONICS IN IIl-V SEMICONDUCTORSMATERIALS AND DEVICESOrganizer: ARO-URI-University of Rochesterand CECOM Center for Night Vision and Electro-Optics1.INTRODUCTION2.SUMMARY -- INCLUDING FOLLOW-UP3.VIEWGRAPH PRESENTATIONSA.Center for Opto-Electronic Svstems ResearchOrganizer -- Gary WicksOptical Properties and Technologies of III-V MaterialsGary WicksSuperlattice DisorderingSusan Houde-WalterOptical Interactions in Indirect Bandgap:Il-V Semiconductors and SiliconDennis HallIII-V Optoelectronics for Optical Communication.Thomas BrownB.4.CECOM Center for Night Vision and Electro-OpticsOrganizer-- L. N. DurvasulaLIST OF ATTENDEESAccesslon'c rNTIS GRA&IDTIC TABJustifioatlonDi stribut on/Availabllty CodesDistSpeo lal
1.INTRODUCTIONThis workshop on "Opto-Electronics in Ill-V Semiconductors: Materials andDevices" represents the third of a series of intensive academic/ governmentinteractions in the field of advanced electro-optics, as part of the Armysponsored University Research Initiative. By documenting the associatedtechnology status and dialogue it is hoped that this baseline will serve allinterested parties towards providing a solution to high priority Armyrequirements. Responsible for program and program execution areDr. Nicholas George, University of Rochester (ARO-URI) and Dr. Rudy Buser,CCNVEO.
2.SUMMARY AND FOLLOW-UP ACTIONRudy Buser started the workshop with a short talk. He mentioned two areas ofIll-V s which are of interest at NVEOC: 'ocal plane arrays of 10 pm detectors; andmonolithic integration--sources; detectors, etc.Ward Trussel spoke about NVEOC's interest in high power laser diode arrays forYAG pumpingSeveral NVEOC personnel expressed interest in high power/high efficiency visible(green) lasers with good beam quality. One way of doing this is by doubling thediode pumped YAG lasers. Dennis Hall received some intercst when hementioned the possibility of green GaP lasers,George Simonis spoke of interest in optoelectronics at Harry Diamond Labs.Their activities include: doping superlattices for optical modulation; resonanttunneling (mainly theory); piezoreflectance studies of Ill-V heterostructures, andlightwave research for microwave radar applications.The original plan was for L. N. Durvasula and I to get together for a short whileat the end of the workshop to decide how future interactions might proceed.Time did not allow this, however, and we agreed to discuss these items on thephone. I tried several times without success during the week following theworkshop to contact Dr. Durvasula. Finally I sent him a letter stating a fewspecific areas where there appeared to be good overlap between research areasat UR and interests at NVEOC. Also stated in the letter was my feeling that theformal presentation structure was appropriate for the first workshop, butsubsequent interactions should consist of smaller, less formal groups and moredialogue.I would estimate that 30 NVEOC personnel attended the workshop.
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Outfin*Crystal growth technologies*Bulk materials properties*Properties of quantum wells and superlattices*Device fabrication technologies
ENERGY GAP (in eV and /im) VERSUS LATTICECO.NSTANT AT 300K FOR COMPOUND SEMICONDUCTORS.0ZnSeAlP0.5.0-1n:Si00eG -25.45.65.86.0a0 (A)6.26.410-H6.6
Heterojunction Energy Bands* jjjujd ConductionOoeeo Ban dAECEA Gaasasadsa
Quantum WellT na a Iz n ZAMGaAsGaAsEANGaAsSuperlattice (type 1)
Important Epitaxiol StructuresLosersDouble Heterostructure (DH)p GaAsp AlGoAsGaAsn AIGoAsn GaAsAl concentration121,m0.2,&Lmmb121mGraded refractive index-Al concentrationseparate confinementheterostructure (GRINSCH)p GaAsp AIGaAsgroded AIGoAsn AIGoAsn GaAsOther Versionsmulti-quantum wellconstant composition, seporaiconfinement heterostructure
Ill-V Materials for Lasersx 2.2 A m -GaInAsSb/AIGaAsSb DH* 1.7x'-1.2 Am GaInAsPAnP DHx 1.2 -0.9 A m-pseudomorphicGaInAs/AIGaAs OW's* X 0.9 0.68 Am - AIxGaj-xAs/AIyGai 1yAs OW'se x 0.65 pm-Gajswtn.48P/AIGaInP
IIl-V's for Long WavelengthPhotodetectors@Lowest bandgap bulk Ill-V is InAs Sb6 leStrained InAsSb Quantum Wellsx, 12 pm*Intraband transitions in the conduction band ofsuperlattices2 A/Watx 10 pmnote: only radiation polarized along growth axis isdetected
Crystal G rowh Tech noI*Bulk Growth Techniques-Bridgeman-Uquid Encapsulated Czochralski (LEC)9Epitaxial Growth Techniques-Uquid Phase Epitaxy (LPE)-Vapor Phase Epitaxy (VPE)-Molecular Beam Epitaxy (MBE)-Metal Organic Chemical Vapor Deposition (MOCVD)
VAPOR PHASE EPITAXYGociAsC3Go2As2 A5.HtECIH2--GoAsT T,Chloilide VPEGHCIHyrdVEHCH-2,GoHa-Hydride VPEGAsT constonthot wllMOCVDMONH3GoAscold wall
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MOLECULAR SEAM EPITAXYCRVOPANELLINOSUBSTRATENEATING fLOCXGGAS WAFEREFFUUSNICELMUTTERCELLSIIIccT[jethea ccoupS00sePOte60S00FL.i tic'.W'oX4AS5P;Nmteia VACUUMcucbl
Mo ciA RBam Eotax (MBE)MAIN ORO TFUSIO CELSSMAM SOUTRCSILED.CHAMBERCHMEMASS SPECAL(LQaD NITONMANIPLATO IISENSTRAjMOEFFUSION .IGCELLE
6as Source MBE SystemMOMBEStandard MBEgrowth chamberDiffusionPump*Pressurecontrol ofqroup V gases*Crack AsHf and PHin same cell
Computer Controlled K- CellsLPUP I I/:3 j(a ,Al, As,Be, Si)CIHAMBER ISOLID SOURCESOptical PortsandREDResidual GasAnalyzerHigh Temperature3" Wafer Track --- '3StageWaer TackCleaningSyatemExpansiono0e-gunDual e-BeamMetallizationResidual GasAnalyzerOptical PortsandNREDCHAMBER # 2GASo(s3P3SURCESTEGa,TEIn,Al, Be, Si)Computer Controlled Gas Sources
DensityofStates2n-1Energy
Electrooptic Effects in Ill-V'sBulk materials - Franz-Keldysh EffectECAEGvA&lOKV/cmShift Absorption Edge * Change refractiv index:An-5 x1O1AElOKV/cm
Electrooptic Effects an HIl 'sQuantum Wells - Excitonic EffectsCase 1. Electric field // Growth axisEcEv*Change shape of potential well 4*shift exciton energy levels 4 shiftabsorption edge #change refracive index.Case 2. Electric field I Growth axis*Field ionize exciton * remove excitonic features from absorptionspectrum 4 change refracive Index.*The excltonic absorption In quantum wells leads to very largeelectroopticeffects:AnA-Fha-5 x 10-2lOKVlcmc -,100 cmlOKVlcm
Edge Emitting LaserEpiv .LayersSubstrate1
Dry Etching Technius optoelectronic Devi*Chemically Assisted Ion Beam Etching Reactive Ion Beam EtchingeReactive Ion EtchingApplications*Integrated lasers no cleaved mirrors*Other integrated devices- lenses- mirrors- modulators
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Experimental:ref:Y. Suzuki and H. Okamoto, J. Elec. Mats. 12,397 (1983)Compare refractive index (dispersion) of bulkAlo.3Gao.oAs to GaAs/AlAs SL's with various barrierthicknesses:38j LE3.7w 3.6,-0.-Et(e-hh)-,,,3.5 "3.4-162,27)w3.3,1.31.41.51.61.7IBPHOTON ENERGY (eV)Note: for a fixed average alloy composition, one canmake large changes in refractive index by tailoringheterostructure dimensions. useful degrees of freedom in device designlaserswaveguides, lenses, modulatorsdetectors
Heterostructures are grown epitaxiallymolecular beam epitaxymetallorganic chemical vapor deposition-,ilayersA)(2-6000GaAs substrateINTEGRATION: grow one structure, use same basematerial for all componentsridge waveguides,define components(e.g.heterostructure lasers) by removing surroundingmaterial (ion beam etching, cleaving, etc.)Disadvantage:scattering, band bending, not planar, etc.Objective: change bandgap and refractive index locallyto define componentsNew Method: smooth abruptness of heterostructureslocally
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Mixing is enhanced by impurity transportref: W.D. Laildig, et al, Appl. Phys. Lett. 38,776 (1981)MASKED Zn DIFFUSION INTOSLZn2As3Si3N4AlAs/GaAs SLsmall bandgaphigh indexlarge bandgaplow index
Lasers:Use layer mixing to:1) tune emission wavelengthref.: M.Camras, et a!, App!. Phys. Lett, 54y,5637(1983).ECfgl-3s*,-122.0l2hW''ISCW CURRET(A)0 PWl
THIS WORK:lID involves electrically active species use applied electric field more accurate diffusion coefficient measurements improved lateral resolution for component definitionZn diffusion1ginSi diffusion'--- -1gm---
mask edgediffusion dominateddrive in mixing profile;little time for sidewaysdiffusion.field-dominatedUse evaporated source or gettering layer:Zn2As3Si3N4VAlAs/GaAs SLUse to study lID mechanism, fabricate components.
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OPTICAL INTERACTIONS IN INDIRECT BANDGAPIll-V SEMICONDUCTORS AND SILICON"Gallium Phosphide, GaPOptical Emission*SiliconOptical EmissionWaveguides
ENERGY GAP (in eV and /m) VERSUS LATTICEONSTANT AT 300K FOR COMPOUND SEMICONDUCTORSZnSe.0AlP0.5CdSAll bCdTeAISb"Si "IGaAs--GaSb"Ge'20--5.6-110.L IS . 11I.4)-5.86.0a,(A)6.26.46.6
GALLIUM PHOSPHIDE, GaPINDIRECT GAP:IMPURITY--2.27 eV AT T 300K.RELATED i,XPoISOVALENTWITHPHOSPHORUSISOVALENT ( ISOELECTRONIC) IMPURITYGaP: NGaP :BiorISOVALENT ( ISOELECTRONIC ) MOLECULEGaPZn-OorGaP:Cd-O0(Nearest-Neighbor Donor-Acceptor Pair)
ENERGY BAND STRUCTUREGaAs - DIRECT ENERGY GAPEConductionBandSphotonE ,r - 1.4ev1ValenceBandSilicon-Crystal Momentum, k0kINDIRECT ENERGY GAP't'IEISCB-1.1 OVjk -0k k1k- CONSERVATION SELECTION RULEI*UNASSISTED,IBAND - TO - BAND, RADIATIVE RECOMBINATION OF ELECTRONSAND HOLES IS FORBIDDEN.PHONON - ASSISTED RADIATIVE TRANSITIONS CAN AND DO OCCUR.I.o
EXCITONS BOUND TOISOELECTRONIC ITY OF NONRADIATIVE AUGER RECOMBINATION IS LOW.PROBABILITY OF RADIATIVE RECOMBINATION IS HIGH.
GaP:NGaP 4 IT NNW-,N-E T ON-BOUNDOA2-- A --o SINGLE.N"IMP' URITY,,,NN2.302.315a.t2.305PHOTON ENERGY (ev)'PAIRS OF/q, jb P.s2.32ATOMS/CC or-;?GEd*dd4'37NN/20I1S.@1.6"K40404-2a2406-.00 60206 a 104A (cu.)OFWINGABSORPTION AT 2.32eeV ON PHONON2(I a ID).uoSLOPE06 0L4,. Rev.ato-6t00F o{z(top ,
G p N2R24G'ree Lc oUlil LL20LED16Absorption02.02.1LASERV.S. Pateyit/AC7)ON3,'71)3'7Le em , Loan2.42.32.2Photon energy', eV(1973)NoAIor'8) andShaklee"Losers io. Xvidmipet0- Samdpap Sernicondvdht.crstgas Voec WA Xsoe)ectronh-.G;inGAPi srerT.1,:.
T7EMEATOTRoMGap: znUIZn-OCd-Oz0-.4TK24a-3StiuIiteJ ETmiSSjonand4 LASerOrverati.st (CtW, '77K) Associite4ISOc)eci'.n c Tra s.liWAt peN. He-fornoi'ORIO1fo1at -fie FeSS nIMcov"C s;ons5ha16f We arcceAI(Wr.VnctrmIAik he' Nfrmiur'ein rc . 7*viesTL optIV Ail*MSe1fVSedletebOIN.arr vd\92180 63 A)(106.4W/cnil'l62
WHAT ABOUT SILICON iPoVI191986CuZn1979.AgCdInAuHg Pb
W. P. DUMKEIBM, YORKTOWN HEIGHTS"INTERBAND TRANSITIONS AND MASER ACTION"PHYS. REV. 127, 1559 (1962).FIRST LINE OF THE PAPERSince the initial operation of the ruby maser, there has beenconsiderable speculation concerning the possibility of observing maseraction in semiconductors such as Ge and Si.ABSTRACT OF THE PAPERThe possibility of using interband transitions to achieve maser action isconsidered. The criterion for maser action Is presented in a way which allows the mostdirect use of optical absorption data. The absorption constant for interband transitions,which is negative corresponding to induced emission when a population inversionexists, is related to the normal absorption constant for direct, indirect, and indirectexciton transitions. Using available absorption data, it is shown that in Ge (Smaser action, using either the Indirect or indirect exciton transitions, wouldbe prevented by absomtion due to free carriers. In GaAs, or othermaterials with a direct gap, however, it is entirely possible that maseraction could be achievbd.)
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Ill-V OPTOELECTRONICS FOR OPTICALCOMMUNICATIONS1. Overview: Communications Systems2. Overview: Modulation/DemodulationSchemes3. Source Stability Requirements forAdvanced Optical Communications4. Methods of Source Stabilization
Historical Perspective:Free Space Optical CommunicationsAncientGreeksMorse Telegraph1840'sBell Telephone1870'sMarconi's Wireless TelegraphRadio. a.1900Coherent Carrier1940'sModulation/DemodulationPhased Locked Receivers1950'sFirst Optical Mixing Observed1955Semiconductor Laser Invented1963Low Loss Optical Fiber1970Free-Space Optical HeterodyneSystems1970'sHigh" speed, low loss single-modefiber links1980'sCoherent Optical Fiber Communicationsproposed1980's
Communications Systems:OpticalFree Space(FiberTelecommunicationsTrunkData TransferLocal Area NetworkSubscriberThere is current interest in:Long repeaterless links.Extremely high capacity links.Wide area distribution.
Direct Detection SystemsTraditional: n-F-u1Dispersi ChannelIntensityModulatedDiode LaserPIN-FETorAvalanche PhotodiodeReceiverWavelength-Division Multiplexed (WDM) Systems:rnrLX1 Dispersiveel-anne3X3X2X4X4tPulse-Position Modulation (PPM) Systems:Low Dispersionna(lowest fundamental limit)Detector
* Direct Detection Systemsideal detector rl 1Average Power PsAverage # of photons per time slot:Ns-PsTB?icoPhoto-electron statistics:p(n) n!epoisson processIdeal photon counting: (no dark count)prob. of error - PE prob(n 0) INs-20.7E-Nsfor PE--99
The Ideal System: Receiver Sensitivity* Heterodyne/Homodyne Systems- No phase noise, perfect ntIncoerentDemod.(Envelope)RFPhotodetectorEs(r, t) Eo(r, t)ii (t) rEs(r, t) ELo(r, t)i (t) (rI e/hw) {Ps PLO 2 t)t2VPTPL Cos (&t 4(t))}0
ry)a(t)a(t) 1 "mark"0 "space"a(t) 1a(t) .67a(t) .33a(t) 0Analog limit (minimum bandwidth)* We are not interested in bandwidthcompression, so use binary.It OTB
ASK IMPLEMENTATION Same modulator technology as directdetection systems.* External modulators only, since directmodulation of semiconductor lasersresults in frequency modulation.(GHz/mA)* Easy detection (in analogy to RFsystems)
MACH-ZEHNDER INTERFEROMETRIC MODULATOR4-Phase Modulator 0102 Cos 2 (AO/2)1 Io/,Phase Modulator 02AO O6 -eA 162* Identical waveguides, equal pathlengths yield constructive interference.* Relative phase shift AO causesdestructive interference for AO n Practical design considerations requiretuning for "on" and "off' states. Top speed 17 GHz[Ref. Gee and Thurmond OFC'84R. C. Alferness, IEEE JQE 17,946 (1981)]
Receiver Sensitivity PenaltyASK Envelope Detection withOptimized Post-detection Filtering3.oim.0Analytical (single-pole IFfilter)C1.0.ONumerical (integrating IF filter)-.7/0.00.0.2.4.Llnewidth/Data Rate.91.0
ry)a(t) 1 mark"a(t) -1 "space"a(t) 1a(t)a(t)a(t) 1-.4 LevelsAnalog limit (minimum bandwidth)* Once again, use binary.IIIIII/
* PSK is a supp ressed carrier modulationtechniqueSSE,,\,E/\,I/I* No energy at ct Co Requires nonlinear phase recoveryscheme.
PSK Implementation:" Simplest possible modulatorconfiguration.Electro-optic (Pockels) effectFree carrier effect (semiconductors)* External modulators only" Detection is difficultas(t) Cos (cost 4(t))weak signal/XIStrong Local OscillatorCOS(COLOt - ( )for error-free detection,4(t) )(t)
PSKM -ER-oP'(I0Eto51I-c-TIc4.03.0-A.2.0-1.0-O0.00.0, . , ,, , ,, g, ,I0.050.1t,* , ,, ,0.150.2NORMALIZED SPECTRAL WIDTH (/)0.25
FSKBinary Representation:(Acchannel spacingM-aryrepresentation#Channels ]M 2m#e(a(t) eia(t)e"mark"cspace"a(t) ei(m I)()cteiIcta(t).a(t) e - i(m )OctBandwidth.ExpansiontechniqueIPower Spectrum SEE()I( CCIL) o
Receiver Sensitivity PenaltyFSK Envelope Detection withOptimized Post-detection Filtering3.0Analytical (single-pole IF filter)4DNumerical (integrating IF filter)-1.0.4Linewidth/Data Rate
Ill-V Optoelectronic Devices: Limitations to SystemPerformanceSemiconductor Lasers:Mode Partitioning(Direct Detection)Phase Fluctuations/Line Broadening(Coherent Detection)Noise Mechanisms(Phase ShiftsInOptical SignalThermal InstabilitiesQuantum FluctuationsHow does this happen?Fabry-Perot ModesAX.nItI- --,,,-Ie-GainIIjI III!IIIISWavelengthLarge changes .Small changes .Mode "partitioning"Line BroadeningProfile
Mode Partitioning1) Time Averaged Laser Spectruma0aaa 1a 222) "Instantaneous" Measurementa -1a0a 1aa 220Assuming the population adiabatically follows thequantum fluctuations:XIa. 00 ConstantConstant flux Is dynamically "partitioned" among themodes.
What happens In a dispersive channel?---- a DispersiveW-W.ao.a ChannelNearly Single Mode][SourceSolutions:- Use the minimum dispersion point In fiber.- Stabilize the diode laser:"Single-mode" lasers require a side modesuppression ratio of about 100:1.Distributed Feedback (DFB) Lasers provide modestabilization.Active RegionDFBLaser Structure
10-6---k 0.18-10-8-RATIO -31)-(MODE-------ok m0. 154(MODE RATIO -42)100-1V:ODE RATIO-Si)10-16L-0.6---1.21.6IN
OPTO-ELECTRONICS IN IIl-V SEMICONDUCTORS MATERIALS AND DEVICES Organizer: ARO-URI-University of Rochester and CECOM Center for Night Vision and Electro-Optics 1. INTRODUCTION 2. SUMMARY -- INCLUDING FOLLOW-UP 3. VIEWGRAPH PRESENTATIONS A. Center for Opto
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performance, and reliability as they pertain to micro- and opto-electronics. The audience for these volumes are those who work in micro- and opto-electronics and photonics, as well as those in many related areas of applied science and engineering. The expecte
seperti dengan adanya dana pensiun setelah masa kerja habis ataupun jaminan hari tua. Pada indikator kebutuhan sosial yaitu kurangnya interaksi antara karyawan . ix dalam bekerja dan sikap acuh tak acuh antar karyawan. Diharapkan dari kebutuhan sosial dapat diatasi dengan perusahaan mengadakan tour atau rekreasi dengan karyawan agar hubungan antar karyawan makin erat, membuat kelompok kerja .