M. Hirose et al., A LIGHTLY DOPED DEEP DRAIN GAAS-MESFET STRUCTURE FOR LINEAR-AMPLIFIERS OF PERSONAL HANDY-PHONE SYSTEMS, I.E.E.E. transactions on electron devices, 43(12), 1996, pp. 2062-2067
An improved GaAs MESFET structure, named a buried p-layer lightly dope
d deep drain (BP-LD3) structure, is proposed, This structure can be fa
bricated by the conventional self-aligned gate and selective ion impla
ntation technologies, and the FET characteristics show a high transcon
ductance, a high breakdown voltage, and a low drain-source resistance,
The lightly doped deep drain characterizing this structure was introd
uced on the basis of a two-dimensional numerical analysis including an
impact ionization for a buried p-layer lightly doped drain (BP-LDD) s
tructure which has been applied for high-speed digital IC's, The simul
ated results clarified that a low breakdown voltage of the BP-LDD stru
cture originates from a high rate of carrier generation due to the imp
act ionization in the lightly doped drain region, The reason is that b
oth electric field and current density become high in the region, In t
he new BP-LD3 structure, the electron current deeply expands due to th
e deep formation of lightly doped drain, therefore impact ionization i
s reduced, This BP-LD3 structure was fabricated and the FET characteri
stics were compared with those of the conventional BP-LDD structure, a
nd a structure which is now being studied for linear amplifies of 1.9
GHz personal handy-phone systems, The measured breakdown voltage of 8.
1 V, transconductance of 360 mS/mm, and drain-source resistance of 2.5
Omega/mm for the BP-LD3 structure indicate high potentiality for anal
og applications.