Vacuum64(2002)245–248 Propertiesofhighgrowthrateamorphoussilicondeposited byMC-RF-PECVD G.Lavareda a,b, *,C.NunesdeCarvalho a,b ,A.Amaral b,c ,J.P.Conde d , M.Vieira e ,V.Chu f a Departamento de Ci # encia dos Materiais, FCT/UNL, Quinta da Torre, 2825-114 MONTE DE CAPARICA, Portugal b Centro de F! ısica Molecular, Complexo Interdisciplinar I, IST/UTL, Av. Rovisco Pais, 1049-001 Lisboa, Portugal c DF, Av.Rovisco Pais, 1049-001 Lisboa, Portugal d DEM, IST/UTL, Av. Rovisco Pais, 1049-001 Lisboa, Portugal e DEEC-ISEL, Rua Cons. Em! ıdio Navarro, 1949-014, Lisboa, Portugal f Instituto de Engenharia de Sistemas e Computadores, Rua Alves Redol, 9, 1000-029 Lisboa, Portugal Abstract Hydrogenatedamorphoussilicon(a-Si:H)thinfilmshavebeendepositedonglassandcrystallinesiliconsubstrates bymagneticallyconfinedRF-PECVD(MC-RF-PECVD)atdifferentRFpowerdensitiesinordertoverifytheinfluence ofthisdepositionparameteronthedensityofstates(DOS)andgrowthrate(R G ).Itwasfoundthatthehighestgrowth rate, 7.8 ( A/s, is obtained for a-Si:H films deposited with an RF power density of 14.3mW/cm 3 . For the DOS calculation, constant photocurrent method (CPM) data have been used. The lowest value of DOS is approximately 8  10 15 /eV/cm 3 andwasobtainedfora-Si:HfilmsproducedwithanRFpowerdensityintherangeof10–20mW/cm 3 . InfraredspectroscopyshowsthatwhentheRFpowerdensityincreases,theconcentrationofSiH 3 groupsdecreasesand theconcentrationofSiHgroupsincreases.At8mW/cm 3 ,amaximumoftheSiH 2 concentrationisobtained.Atthis point, a maximum of the optical gap (1.9eV) is observed and a minimum of the dark conductivity is verified. We concludethatthebestfilmsareachievedinanRFpowerdensityrange(7.1–21.4mW/cm 3 )forwhichanincreaseofSiH andadecreaseofbothSiH 2 andSiH 3 aresimultaneouslyobtained.Thereafter,forhigherpowerdensities,aninversion ofDOSandgrowthratebehaviourareobservedduetoionbombardment. r 2002 Elsevier Science Ltd. All rights reserved. Keywords: DOS;Growthrate;Hydrogenbonding;RFpowerdensity;IRspectroscopy 1. Introduction The purpose of most amorphous silicon thin filmsstudieswastoprovideamaterialappropriate asasemiconductorforelectronicsystems.Nowa- days, a wide range of techniques are available to deposita-Siasathinfilmonasubstrate,suchas thermalevaporation,sputtering,hot-wireandRF plasmaenhancedchemicalvapourdeposition(RF- PECVD). So far, among these techniques, the PECVD has proved to produce the best quality material for thin film applications with low DOS (E10 15 /eV/cm 3 )[1].Thisisduetothepresenceof an appropriate bonded hydrogen content in the films(a-Si:H)whichcausesthebroadeningofthe *Corresponding author. Centro de F! ısica Molecular, IST/ UTL,ComplexoInterdisciplinarI,Av.RoviscoPais,1049-001 Lisboa,Portugal. E-mail address: pccanc@alfa.ist.utl.pt(G.Lavareda). 0042-207X/02/$-seefrontmatter r 2002ElsevierScienceLtd.Allrightsreserved. PII:S0042-207X(01)00293-7