쌍극자 전위장벽을 갖는 갈륨비소 전계효과 트랜지스터에 관한 연구

학위논문(박사) - 한국과학기술원 : 전기 및 전자공학과, 1994.2, [ ii, 105 p. ]A novel GaAs FET structure with $\delta_n-\delta_p$ DIpole potential Barrier(DIBFET) is proposed and fabricated. The $\delta_n$- and $\delta_p$- layer make transversal electric field, and this forms the potential barrier to the electrons. A conventional $\delta$-doped structure has many advantages, but it has fundamental problems of the ionized impurity scattering near the $\delta$-dope plane. The potential barrier of DIB-structure can push up the electrons near the $\delta$-doped plane from the impurity plane to the undoped channel layer. Thus, it is expected that the transport characteristics of DIB-structure will be improved. The measured carrier density and drift mobility at the undoped channel layer obtained above $1\times10^{18}cm^{-3}$ and $3700cm^2/V$\cdot\sec$from the C-V and FATFET method, respectively. They show the improved transport characteristics considering the carrier density, as expected. In this thesis, the measured data and the results of one-dimensional numerical calculation are compared. The numerical calculation gives the C-V and channel-conductance characteristics. From the calculations, the sensitivities of the device characteristics such as the variations of channel conductance and capacitance about the doping density of$\delta$-layer and the thickness of the undoped channel layer are shown. The fabricated DIBFET with 0.8$\mu$m gate length has the maximum extrinsic transconductance of 407mS/mm and the current density of 550mA/mm at zero gate bias condition. The high output resistance of 260$\Omega\cdot$mm is measured, and the high value of output resistance is due to the potential barrier effects of the dipole layer. In RF applications, the measured extrinsic current gain cutoff frequency of DIBFET with 0.8$\mu$m gate length is about 16.7GHz, the extracted intrinsic current gain cutoff frequency is above than 22GHz. The obtained cutoff frequencies of maximum available power gain and of unilateral power gain are 67GHz and 82GHz, respe...한국과학기술원 : 전기 및 전자공학과

Submicron photolithography

학위논문(석사) - 한국과학기술원 : 전기 및 전자공학과, 1989.2, [ 1책(면수복잡) ]한국과학기술원 : 전기 및 전자공학과