TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Parameter: At least one of the emitter region and the surface field region has a resistance of 1 x 10-6 to 10-3 Omega -cm. A concentration of the metal material contained in the at least one of the emitter region and the surface field region is 1 x 1015 to 1021 atoms/cm2. At least one of the emitter region and the surface field region comprises a first portion contacting the substrate and made of amorphous silicon and a second portion positioned on the first portion and made of the amorphous metal silicide, and where the first and second regions are doped with the second impurity or the third impurity; where the first portion has an impurity doped concentration of the second impurity or the third impurity equal to an impurity doped concentration of the second portion of the second impurity or the third impurity; and where the impurity doped concentration of the first and second portions is 1 x 1016 to 1021 atoms/cm3, respectively. An impurity doped concentration of the second impurity or the third impurity contained in the at least one of the emitter region and the surface field region is changed in accordance with a change in a thickness of the at least one of the emitter region and the surface field region, where the impurity doped concentration of the second impurity or the third impurity contained in the at least one of the emitter region and the surface field region increases from a contact surface of the substrate and the emitter region to an opposite surface of the emitter region or the substrate and the surface field region to an opposite surface of the surface field region. The impurity doped concentration of the second impurity or the third impurity contained in the at least one of the emitter region and the surface field region increases from 1 x 1016 to 1021 atoms/cm3. At least one of the emitter region and the surface field region comprises a first portion contacting the substrate and made of amorphous metal silicide and a second portion positioned on the first portion and made of the amorphous metal silicide, and where an impurity doped concentration of the second or third impurity in the first portion is less than an impurity doped concentration of the second or third impurity in the second portion, where the impurity doped concentration of the first portion is 1 x 1010 to 1015 atoms/cm3, and the impurity doped concentration of the second portion is 1 x 1016 to 1021 atoms/cm3; or where the impurity doped concentration of the first portion is 0 atoms/cm3, and the impurity doped concentration of the second portion is 1 x 1016 to 1021 atoms/cm3.    TECHNOLOGY FOCUS - METALLURGY - Preferred Component: The metal material comprises at least one of chromium (Cr), aluminum (Al), cobalt (Co), hafnium (Hf), molybdenum (Mo), nickel (Ni), lead (Pd), platinum (Pt), tantalum (Ta), titanium (Ti), tungsten (W), and zirconium (Zr).