Temperature Dependence of Substrate and Drain Currents in Bulk FinFETs

Abstract

<para xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> The temperature <formula formulatype="inline"><tex>$(T)$</tex></formula> dependence of <formula formulatype="inline"><tex>$I_{\rm SUB}$</tex></formula> and <formula formulatype="inline"><tex>$I_{D}$</tex> </formula> in bulk FinFETs was investigated for the first time. Both n- and p-channel devices with thin fin body width showed the abnormal increase of <formula formulatype="inline"><tex>$I_{\rm SUB}$</tex></formula> at high <formula formulatype="inline"><tex>$T$</tex></formula>, which can be explained by stress-induced bandgap narrowing. <formula formulatype="inline"><tex>$I_{\rm SUB}$</tex></formula> and <formula formulatype="inline"><tex>$I_{D}$</tex> </formula> were investigated as parameters of <formula formulatype="inline"><tex>$T$</tex></formula> and fin body width <formula formulatype="inline"><tex>$(W_{\rm fin})$</tex></formula>. It was shown that thinner <formula formulatype="inline"><tex>$W_{\rm fin}$</tex></formula> gets higher stress. With increasing <formula formulatype="inline"><tex>$T$</tex></formula>, the <formula formulatype="inline"><tex>$I_{D}$</tex> </formula> of n-channel bulk FinFET with thinner <formula formulatype="inline"><tex>$W_{\rm fin}$</tex></formula> is increased since electron mobility is increased by tensile stress. The threshold voltage decrease becomes significant with decreasing <formula formulatype="inline"><tex>$W_{\rm fin}$</tex></formula> by the bandgap narrowing, which contributes to the <formula formulatype="inline"><tex>$I_{D}$</tex></formula> increase. The <formula formulatype="inline"><tex>$I_{\rm SUB}/I_{D}$</tex></formula> of n-channel bulk FinFET was studied by changing <formula formulatype="inline"><tex>$W_{\rm fin}$</tex></formula> and <formula formulatype="inline"><tex>$ \hbox{1}/V_{\rm DS}$</tex></formula> as a parameter of <formula formulatype="inline"><tex>$T$</tex></formula>. </para>