| Summary: | 碩士 === 國立清華大學 === 電子工程研究所 === 94 === In this thesis, we do analysis of boron and phosphorus doped microcrystalline silicon and undoped microcrystalline silicon thin films deposited on glass and 4` wafer substrates by electron cyclotron resonance chemical vapor deposition (ECRCVD). Meanwhile, by using CAD(Computer Aided Design) tools, we optimized the device thickness structure. Finally, according to our best recipe, fabricate microcrystalline thin film solar cell, and I-V measurement are taken as the device characteristics.
In experiment, we fixed substrates temperature at 250℃, microwave at 1150W, pressure at 20mTorr, change flow rate of H2 observed the films characteristics. The film thickness, crystalline fraction, grain size, bonding configurations, dark and light conductivities, doped concentration, resistivity of μc-Si:H films were measured and analyzed by Raman spectroscopy, FTIR spectroscopy, X-ray diffraction (XRD),Nanospac andα-step depth profile, I-V measurement, 4-point probe, and SEM, SRP. The Etching model was introduced to explain the effect of hydrogen dilution ratio on the structure of uc-Si:H films. Hydrogen-etching reaction was explored as a major dynamics in determining the crystallization of silicon films. The preferential elimination of energetically unfavorable configurations by hydrogen etching attributes
to low-temperature-crystallized silicon films. In finish analysis of thin films, we can use best recipe fabricate PIN thin film solar cell, and measurement at Tze Chiang Foundation of Science and Technology.
The experiment results show that, hydrogen dilution ratio at 92% having high crystalline fraction(>90%), and large grain size(>250A), hydrogen dilution ratio between 40% to 96%, the bonding configurations from 2000cm-1 to 2100cm-1, and hydrogen content decreased when hydrogen dilution ratio increased. the doped concentration at N-type is about 1.24e17cm-3 , P-type is about 3.67e17cm-3 . in device measurement results, the Voc is about 0.4999V, Isc is about 0.33mA, Fill factor is about 20.62%.
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