Generation of Giant Thermo-electric Power by Ultra-heavily Boron Doped SiGe and Its Application

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Crystallinity :Crystalline growth of SiGe films was slightly observed to take place at 400℃ from XRD measurement. Below that the films were amorphous structure. The films were confirmed epitaxially grown from RHEED observation. Above 500℃, crystallinity was improved.Resistivity :Until 400℃, film resistivity decreased with increasing growth temperature but above that, resistivity was increased again. This phenomena is explained that at low temperature carrier is not generated because of the amorphous structure. While crystalline growth proceeds, carrier comes to be generated. Under almost perfect crystalline structure, however, resistivity increases again because of intrinsic semiconductor resulting in no carrier genneration. The reason of low resistivity at 400℃ is considered that appropriate crystalline defects generated carriers, which could conduct within the crystallized region.Seebeck coefficient :SiGe films prepared showed large Seebeck coefficients of 1.5-2.0mV/K which is more than 3 times larger than that of bulk SiGe. No special coreration was observed on Seebeck coefficient with samples.Thermo-electric performances :Power factor was estimated from the Seebeck coeffcient and resistivity and showed as high as 7.2x10^<-2>Wm^<-1>K^<-2>. Moreover, the non-dimensional figure of merit Z reached ZT=1.3 at room temperature. This value shows useful for practical use.