O. Arisumi et al., ANALYSIS OF SI-GE SOURCE STRUCTURE IN 0.15 MU-M SOI MOSFETS USING 2-DIMENSIONAL DEVICE SIMULATION, JPN J A P 1, 35(2B), 1996, pp. 992-995
We describe the technological potential of the bandgap engineering tec
hnique involving a Si-Ge source structure in a fully-depleted SOI MOSF
ET to suppress the Boating-body effect. The Si-Ge layer fabricated in
the source region acts as an absorber for excess holes in the channel
region. The detailed mechanism as well as the structure dependence in
SOI MOSFETs with a gate length of 0.15 mu m have been studied using a
two-dimensional device simulation. It has been found that the improvem
ent in BVds is strongly dependent on the lateral position of the Si-Ge
layer relative to the source-to-channel pn junction. It is further pr
edicted that encroachment of the Si-Ge layer into the channel region a
chieves the maximum BVds improvement. The BVds improvement is predicte
d to reach 1.5 V if it proves possible to lower the energy barrier at
the pn junction in the case where Delta E(g) = 0.2 eV.