Optical properties of thin films on transparent surfaces by ellipsometry; internal reflection for film covered surfaces near the critical angle

The a pplication of ellipsomctr y to t hc dcterm ination of t he op tical proper t ies of t hin film s ,?r~ transparent s ubstrates b y t h e usc of intcl'l1al r efiection and a ngles of incidence ncar the cl'ltlcal an gle for total r efi ection is dcs cribed a nd illust rated.Foul' cases are co ns idcrcd : 1. t he angle of i ncidence, (J;, is less t han eithcr t he cr itical a n IT le for total r eflection bctween t he s ubstrate, a nd the film , 0e " ' , a nd t he criti cal a ngle betw~e n t he substrate and t he sur-roundll1& mec\ll~m , (Je ' • 3 ; 2. 8e , • 3 > Oi>.(J , I.,; 3. 0, 1,3< Oi< O, " '; and '!. 0, 1.3 < 0,>11, 1,2.For case 1, fit ce r ta~!1 Cri tICal ~l aili es of .film t hl ck ncss d iln.d ref l:a ctive index n" t he refi ected li gh t mfly be p ola ll zed WIth .Its electl'l c v e ~t<? r eltll er e nt irely Hl or normal to t he plan e of in cid en ce .N ear thcs?co nd it io ns t he se ns l t l v ~ty of cll ipso met l'l c meas ure men ts is extrem ely high, but ~h e Intensity of the refl ect.crll igh t IS very low .Except under t hese condition s t hc in tcns itv IS adeq ua te for eXIJerim cnt a l meas urem en ts, as it is a lso in Cfl SC 2. For casc 1 it is alway"s po.sslbl c to determ ine on, a nel d by a Single m e ~s urcm c n t ; for casc 2 th is is possib lc o nl y tor t hin fi lms , For cases .) a nd 4, il nel CflSC 2 fo r t hi ck fi lms, only one of t hesc may be determincd .Under t hese concli tlOn s, howc ver , t hc rc fl cct ivity is 100 pcr ce n t .;,!