Daim ntawv thov ntawm Microscope hauv Strategic Emerging Industry LED
1. Daim ntawv thov tshwj xeeb ntawm Leica optical microscope thiab scanning electron microscope hauv LED upstream substrate khoom (sapphire khoom):
1. Taw qhia txog cov khoom siv sapphire substrate
Vim tias sapphire muaj cov rwb thaiv tsev zoo, tsis tshua muaj dielectric poob, kub tsis kam thiab corrosion kuj. Zoo thermal conductivity, siab txaus nyob rau hauv mechanical zog. Thiab tuaj yeem ua tiav rau hauv qhov chaw tiaj tus. Lub teeb kis tau tus mob yog dav. Yog li ntawd, nws yog dav siv nyob rau hauv ntau yam kev lag luam, lub teb chaws tiv thaiv thiab kev tshawb fawb kev tshawb fawb. Nyob rau tib lub sijhawm, nws tseem yog cov khoom siv substrate zoo rau lub teeb-emitting diodes nrog ntau yam kev siv. Qhov tshwm sim lub teeb-emitting diode yog qhov zoo tshaj plaws semiconductor light-emitting device substrate khoom rau sapphire substrate substrate nyob rau hauv lub high-brightness lub teeb-emitting diode tsev neeg ntawm lwm tiam fluorescent teeb qhov chaw. Tam sim no, cov high-brightness teeb-emitting diodes tau lug siv nyob rau hauv advertising, tsheb teeb, ntsuas teeb; thiab kev khiav hauj lwm teeb thiab lwm yam teb. Nrog rau daim ntawv thov ntawm high-brightness lub teeb-emitting diodes.
Sapphire (Sapphire) yog ib qho siv lead ua ntawm alumina, tseem hu ua corundum. Sapphire siv lead ua muaj cov khoom siv kho qhov muag zoo, cov khoom siv kho qhov muag thiab tshuaj lom neeg ruaj khov, lub zog siab, siab hardness, thiab yaig tsis kam, thiab tuaj yeem ua haujlwm nyob rau hauv qhov hnyav ze li 2000 degree. Raws li kev tshawb fawb, tsuas muaj plaub yam khoom siv substrate tuaj yeem siv rau LEDs tam sim no (saib Daim duab 1 hauv qab). Raws li ib qho tseem ceeb kev siv lead ua siv lead ua, sapphire tau tsim ib tug kuj fashionable thiab paub tab daim ntawv thov nyob rau hauv lub LED kev lag luam.
2. Daim ntawv thov
Qhov txawv txav birefringence ntawm sapphire siv lead ua tuaj yeem txheeb xyuas tau siv Leica's polarizing microscope. Nyob rau hauv qee qhov xwm txheej, nrog kev pab los ntawm lub lens conoscopic, lub interferogram ntawm cov siv lead ua tuaj yeem pom los txiav txim siab qhov axiality ntawm cov siv lead ua, uas yog siv los soj ntsuam seb qhov kev taw qhia ntawm txhua lub wafer zoo li cas, thiaj li txiav txim siab seb lub substrate puas yog. zoo los phem.
2. Daim ntawv thov ntawm Leica microscope thiab scanning electron microscope nyob rau hauv zus tau tej cov LED epitaxial wafers thiab cov txheej txheem ntawm kev npaj ntawm LED chips
1. Taw qhia txog LED Epitaxial Wafer
Lub hauv paus ntsiab lus ntawm LED epitaxial wafer txoj kev loj hlob yog: ntawm lub substrate (tsuas yog sapphire, SiC, Si) rhuab mus rau qhov tsim nyog kub, cov gaseous tshuaj InGaAlP yog thauj mus rau lub substrate nto nyob rau hauv ib tug tswj, thiab ib tug tshwj xeeb ib tug siv lead ua zaj duab xis yog zus. . . Tam sim no, LED epitaxial wafer kev loj hlob thev naus laus zis feem ntau yog siv cov hlau organic chemical vapor deposition method (MOCVD)
2. LED nti qhia
LED chips, tseem hu ua LED teeb-emitting chips, yog cov khoom tseem ceeb ntawm LED teeb, uas yog hais txog PN hlws ris. Nws lub luag haujlwm tseem ceeb yog hloov hluav taws xob rau hauv lub teeb lub zog, thiab cov khoom tseem ceeb ntawm cov nti yog monocrystalline silicon. Semiconductor wafer yog tsim los ntawm ob qhov chaw, thiab ib feem yog P-hom semiconductor, thiab lub qhov nyob hauv nws txoj haujlwm, thiab lwm qhov kawg yog N-hom semiconductor, thiab ntawm no feem ntau yog electron. Tab sis lub sij hawm no ob hom semiconductors ua ke, nruab nrab ntawm lawv, tsuas yog tsim ib qho kev sib tshuam PN. Thaum hluav taws xob tam sim no ua rau cov nti no los ntawm lub sij hawm xaim, electron yuav raug thawb mus rau P koog tsev kawm ntawv, thiab hauv P koog tsev kawm ntawv, electron yog nrog lub qhov recombination, ces yuav xa lub zog nrog daim ntawv ntawm photon, lub hauv paus ntsiab lus ntawm LED luminescence uas nyob ntawm no. Thiab lub wavelength ntawm lub teeb piv txwv li cov xim ntawm lub teeb, txiav txim siab los ntawm cov khoom tsim PN hlws ris.
3. Daim ntawv thov:
a) Siv lub tshuab ntsuas hluav taws xob ntsuas hluav taws xob txhawm rau txheeb xyuas qhov dislocation corrosion morphology cov ntaub ntawv ntawm lub dav hlau siv lead ua tom qab kev loj hlob ntawm epitaxial wafer;
Lub ntsiab lus muab los ntawm dislocation corrosion morphology ntawm lub dav hlau siv lead ua: qhov dislocation corrosion ntawm txhua tus qauv muaj cov duab sib txawv thiab txiav txim siab los ntawm pawg taw tes ntawm cov siv lead ua thiab cov qauv ntawm cov siv lead ua. Lub luag haujlwm ntawm cov tshuaj etchant yog txhawm rau rhuav tshem cov kev sib cuam tshuam ntawm cov molecules thiab atoms hauv cov siv lead ua. Cov uas muaj cov ntawv cog lus me me raug rhuav tshem ua ntej, yog li tsim cov pob txha ntawm cov duab tshwj xeeb. Yog li ntawd, cov duab zoo thiab kev nthuav qhia zoo tshaj plaws ntawm cov ntsiab lus ntawm cov pob txha pob txha tuaj yeem cuam tshuam qhov zoo ntawm cov khoom siv lead ua.
Txhim kho qhov zoo ntawm epitaxial lattice thiab txo cov khoom tsis xws luag yog qhov yuav tsum tau ua ua ntej rau kev tsim cov khoom siv hluav taws xob siab thiab kev ntseeg siab, txwv tsis pub nws yog qhov nyuaj rau kev tsim nws los ntawm lwm txoj kev. Kev cuam tshuam ntawm cov khoom siv lead ua zoo ntawm LED epitaxial cov ntaub ntawv ntawm kev ntseeg tau ntawm cov cuab yeej tau qhia meej. Los ntawm kev tswj kom zoo ntawm cov ntaub ntawv epitaxial, nws yuav tsum tau txo qhov tsis xws luag ntawm cov ntaub ntawv, txhim kho cov siv lead ua zoo ntawm epitaxial txheej thiab zoo txhim kho kev ntseeg siab ntawm LED li.
b) Chip tshuaj xyuas ua ntej ntim: Tshawb xyuas qhov chaw ntawm cov khoom siv nrog lub tshuab ntsuas qhov muag los txiav txim seb puas muaj kev puas tsuaj thiab pitting, seb lub nti loj thiab electrode loj npaum li cas raws li cov txheej txheem, thiab seb cov qauv electrode puas tiav.
c) LED nti oxidation thickness: kev tshawb nrhiav muaj xws li kev sib piv xim, ntug suav, cuam tshuam, ellipsometer, engraved koob amplitude meter thiab scanning electron microscope;
d) Kev ntsuas qhov tob ntawm qhov sib txuas ntawm cov nti wafer: lub thickness nrhiav tau ntawm PN hlws ris qhov tob ntawm LED nti wafer los ntawm lub tshuab ntsuas electron
e) Daim ntawv thov ntawm scanning electron microscopy nyob rau hauv kev tshawb fawb ntawm nto roughening tshuab nyob rau hauv lub etching txheej txheem ntawm LED chips: lub nto roughening tshuab daws qhov teeb meem ntawm tag nrho cov kev xav ntawm lub teeb nrog ib tug teeb meem lub kaum sab xis siab tshaj lub kaum sab xis vim lub refractive index ntawm semiconductor. cov ntaub ntawv (nruab nrab 3.5) yog ntau dua li huab cua. Qhov poob los ntawm kev tawm. Lub emission ntawm lub teeb nyob rau hauv lub roughened nto yog heev random, thiab ib tug loj tus naj npawb ntawm thwmsim yuav tsum tau mus kawm lub roughness thiab roughness nplai ntawm lub teeb emission npaum li cas. Thaum lub teeb nkag mus rau hauv huab cua nrog qhov ntsuas qis qis los ntawm GaP, cov khoom siv ntawm LED qhov rais txheej nrog lub siab refractive index, tag nrho cov kev xav yuav tshwm sim, thiab ntau lub teeb tawm yuav ploj. Txoj kev roughening nto tuaj yeem cuam tshuam tag nrho cov kev xav thiab txhim kho lub teeb extraction efficiency. Lub tshuab ntsuas hluav taws xob ntsuas hluav taws xob tuaj yeem ncaj qha saib cov qauv saum npoo ntawm cov qauv tom qab nto roughening, thiab sib piv qhov roughness ntawm qhov chaw ua ntej thiab tom qab roughening. Lub tshuab ntsuas hluav taws xob ntsuas hluav taws xob muaj qhov tob loj ntawm qhov chaw, thiab cov duab yog tag nrho ntawm peb-dimensionality. Nws tuaj yeem soj ntsuam cov qauv peb-dimensional kob ntawm qhov chaw roughened.
