Laser Raman Spectroscopic Studies On The Wet Etching, Optical Properties Of Silicon And The Formation Of Cobalt Silicides

Silicon is one of the most abundan elementS in earth. Such a material is very strOng, sedlarto steel in modulus of elashcity, without mechanical hysteresis, POsses a good thennalconduchvity and a low thermal expansion coefficient. With these featUres and the matuIation ofsilicon technology, silicon has been the most deePly and systematicaIly inveshgated tnateriaIs,which maks it the most twrtant and widest aPplied among all semiconductor materials.However, the pursuit for the advanced techniques, thetnnnents and devices is everiasting, such asfaster sPeed, better fUnchon and lower price. In viewing the fast development of informahon andrnaerials sciences in the new centUry, the rniniaturizaon and intelligenthation of thesilicon-based device will be the rnain direction in this field. Reeently, there are three hot researchtopics f (i) the sche processing and fabrication, (ii) the twrovement and exP1oring of thedevice funchon and (iii) the interconnechon and packaging materials.In order to W a breakthrugh in these three aPproaches, one must get deeP insights intOthe sdse sthectUre and bonding coallgUration on the silicon sdrice, such as SifH, SiE Si.Oand Si:metal, which directiy whuence even deterTnine the physical and chendcal proPetries ofsilicon and the subsequent fabrication and packaging procedur. Therefore, how to correchycharacterize and control the sdrice configUrahon is a key issue for the fundamental inveshgahonand aPplied fabricahon. Spectroscopies, especially the vibration spectroscopies (Raman, IR andSFG), are toortant tools in characterizing the 1ocal bonding environrnents in sedriconductors.However, due to their own 1dritation of these individua1 techniques and the critical condition insilicon technology, such as the utilization of high corrosive gas or solution, it is difficult toperfrm an in sitU research by using all kinds of spectroscopies. Obviously, it is necessary toestablish a suitable technique, especially in situ technique. The advantages of Ramanspectroscopy in the sbole experimental setuP, the ease of obtaining the signal in the lowfrequency region, and the weak intederence from solution signal, especially, its high strUctUraIselectivity to the nanomaterials and the solid phase transition, makes it a prondsingcharacterization tool for silicon. However, its low detechon sensitivity and the rigorous workingcondition in silicon tecIiniques restrict itS widespread aPplication. As a consequence, uP to now,the in sitU Raman inveshgation in mis field is still very limited.Accordingly, the emphasis of mis dissertation is placed first on the deve1oPment ofmethodology. T'he work includes how to investigate in sitU the reaction of silicon under reactioncondition by Raman SPectroscoPy. Then we systematically investigated the following issuesreIated to three hot topics in silicon industryt (i) the wetetching process of silicon including theelectrOcheAncal etching process and the hahal oxidahon process of the hydrogenated siliconsurface in various media, (ii) the fOrmation process of porous silicon and the Ramanenhancement effect of silicon, (lii) the reaction of cobalt film on the silicon schce (f On'naton ofcobalt silicides) under high temPeratUr. The main conclusions of the work are listed as follows f(1) Establishing suitable methods fOr the in sitiI Raman investigation on thereaction of the silicon surfaceThe emPhasis is placed on how to exert the full POtentiaI and advantage of RamanspectrOscopy and avoid the negative dence of the critical reaction condihon on the OPeratoand the instoents. The followmg sthetegies were adaPted fA. OptiAnzation on the exPedelltal condition of the instIUInent. Even on the assist ofconfocal Raman ndcroscoPe as the present new generation Raman insmimen, theunenhanced Raman signal from xnonolayer adsorbate can oIily be obtained aller adedicated oPtimhation on the exPedental conditions. Several aPProaches have beenmade, such as to se1ect sui...