| Silicon (Si) based electronics have been widely developed and studied in industries. As an important branch of Si based electronics, photodiode technologies are widely used in photonic detection and the photovoltaic field. Low-cost thin-film Si is especially useful for solar cells. We studied the metal induced growth (MIG) of micro-crystal Si (mc-Si) and use of Schottky diodes to evaluate the mc-Si. This thesis focused on the fabrication of metal-insulator-semiconductor Schottky photodiodes combining with different types of Si, insulator layers, pre and post surface treatments. To grow mc-Si, 500A thickness palladium (Pd) and 300A thickness cobalt (Co) were evaporated as the metal catalyst on the silicon substrate covered with silicon dioxide. The 5 um thickness mc-Si films were deposited using two-step DC sputtering at 575°C. The Pd and Co were consumed to form silicide to provide nucleation sites for mc-Si growth at 50 W low power step. Then, mc-Si films were grown at a high deposition rate in the 150 W high power step. SiO2 grown by thermal oxidation, Al2O3 and HfO2 achieved by atomic layer deposition were applied to MIG-Si, single crystal n-Si and single crystal p-Si as insulator layers. Au and Cr were used to form a Schottky junction on n-Si and p-Si, respectively.;The I-V performance of all three groups of different Si based photodiodes under both dark and illumination conditions were illustrated in the thesis. The fill factor, barrier height, ideality factor and m-factor in log-log plot were calculated. SiO2 acted as good insulator layer on all three different Si based MIS photodiodes. The photo I-V measurements of devices based on MIG-Si, n-type sc-Si and p-type sc-Si with SiO2 as an insulator layer provided a Voc of 0.18, 0.2 and 0.44V; a Jsc of 6.59x10-4, -7.39x10-3 and 1.29x10 -2 A/cm2; and a fill factor of 0.4, 0.28 and 0.39, respectively.;In addition, Al2O3 and HfO2, which are widely used in capacitors with high dielectric constants, were applied to MIS photodiodes by atomic layer deposition. To achieve high quality Al 2O3 or HfO2 films, pretreatments on the silicon surface and post annealing of insulator film were used. As a result, pretreatment on single crystal n-Si showed a large improvement comparing with the same structure device with SiO2 as an insulator. Ozone cleaned HF-last n-type sc-Si with 20A HfO2 gave the best result: a Voc of 0.48 V, a Jsc of 1.42x10-2 A/cm 2, and a fill factor of 0.37. |
