Com o objetivo de melhor entender os processos de dopagem por implantação iônica de dopantes substitucionais e intersticiais, foram estudadas as propriedades eletro-ópticas de películas de Si : H-A implantadas com fósforo, potássio e silício. As películas foram depositadas em diferentes reatores do tipo PECVD, implantadas a temperatura ambiente e posteriormente recozidas. Em função da temperatura de recozimento mediu-se a condutividade no escuro, o produto ETA-MU-TAL, a energia de ativação e o fator pré-exponencial da condutividade. A variação da condutividade em função da temperatura de recozimento foi atribuída ao deslocamento do nível de FERMI. Confirmou-se a maior eficiência de dopagem do k com respeito ao P, tendo sido obtidas diferenças de duas a quatro ordens de grandeza no valor da condutividade de películas implantadas com os dois dopantes. Verificou-se que a melhor temperatura de recozimento independe da temperatura de deposição das amostras não dopadas numa grande faixa de concentração de dopantes. A temperatura ótima é cerca de 340°C e se mostra válida para os dois tipos de dopantes estudados. Para doses elevadas, a melhor temperatura de recozimento é cerca de 260°C e os danos introduzidos pela implantação não são totalmente recuperados através de tratamento térmico.

Aiming at a better understanding of the doping processes by ion implantation of substitutional and interstitial dopants, the electro-optical properties of hydrogenated amorphous silicone films implanted with phosphorus and potassium were studied. The studied peak concentration range was 8 X 1015 to 1.5 X 1021 atoms.cm-3 for phosphorus and 5 X 1018 to 5 X 1020 atoms.cm-3 , in the case of potassium. Two different PECVD-type reactors were used to deposit the amorphous silicon films. The ion implants were done at ambient temperature. A post-implant thermal annealing step was done to activate the dopants and to recover implant structural damages. The dark conductivity, the µ product, the activation energy and the conductivity pre-exponential factor were studied as a function of the temperature. Photo-sensitivity measurements were also done. Silicon ions were implanted in the amorphous silicon films in order to study the radiation damage effects independently of the doping effects. The same thermal annealing procedures of the dopant implants were used. A wide variation of conductivity values as a function of the annealing temperature, ascribed to the Fermi level shift, was found. The better doping efficiency of the interstitial dopant, potassium, when compared to phosphorus, an interstitial dopant, was confirmed. Two to four orders of magnitude differences in the conductivity values for amorphous silicon films implanted with phosphorus and potassium were found. It was verified that the best post-implant annealing temperature is not dependent on the amorphous silicon film deposition temperature in a wide range of dopant concentration (< 1 X 1021 atoms.cm -3 ). The optimum temperature is ~340°C for both dopants, phosphorus and potassium. For doses resulting in concentrations higher than 1 X 1021 atoms.cm-3 , the best annealing temperature was found to be ~260°C. For those high ion doses, the implant damage could not be totally annealed. The present study was meant to contribute for the viability of the ion implant processing in the fabrication of amorphous silicon electronic devices.