Light-Passivation Effect on P-type Porous Formation

• Main Authors: Ji-yuan Jang, 張繼元
• Other Authors: Tien-hsi Lee
• Format: Others
• Language: zh-TW
• Published: 2013
• Online Access: http://ndltd.ncl.edu.tw/handle/49653470426639782507

碩士 === 國立中央大學 === 機械工程學系 === 102 === Porous silicon was discovered in 1956, Uhlir accidentally discovered a black film layer on the wafer in electrochemical polishing on silicon wafers.The film is called porous silicon. After the decades,the researches on porous silicon increase widespreadly on different areas such as MEMS, semiconductor devices, solar cells, biomedical engineering, etc. In general, the P-type silicon wafer of the implantation of boron (III A)with the electron-hole pairs can normally use electrochemical etching method to produce porous silicon;the N-type silicon of the implantation of arsenic (V A)with only electron,it must be use UV irradiation to let the wafer produce hole,and the electron can conduct indirect transitions produce,finally the N-type silicon wafer can produce etching reaction to make the porous silicon structure in etching process. Thus,the photoelectrochemical etching studies and literature on the N-type silicon wafers are numerous, but most scholars rarely reasearch the photoelectrochemical etching of the P-type silicon wafer. This study is reasearching the electrochemical etching for the P-type silicon wafer combined with different power output of the laser light.The etching rate is observed for the different light energy. This study found that the energy of laser light irradiation is stronger,the etching reaction is harder to be advanced. Finally, in order to analyze the activation energy, this study use Arrhenius equation deduced the relation between the different light power, the etching rate, and the activation energy. This technology can replace the photoresist coating and removing steps of the lithography technology on MEMS and the semiconductor etching process, in addition to the process time can be shortened and reduce costs, but also the size becomes smaller as small as nanometer.