Title :
30 GHz polysilicon-emitter and single-crystal-emitter graded SiGe-base PNP transistors
Author :
Harame, D.L. ; Stork, J.M.C. ; Meyerson, B.S. ; Crabbe, E.F. ; Scilla, G.J. ; de Fresart, E. ; Megdanis, A.E. ; Stanis, C.L. ; Patton, G.L. ; Comfort, J.H. ; Bright, A.A. ; Johnson, J.B. ; Furkay, S.S.
Author_Institution :
IBM, Yorktown Heights, NY, USA
Abstract :
The AC performance of SiGe-base PNP transistors has been limited by a valence band barrier at the base-collector junction caused by the retrograde Ge profile. A two-times improvement in f/sub T/ over previous work on SiGe-base PNPs is reported. The improvement was achieved by using a narrow base profile (W/sub B/=50 nm) and by grading the Ge across the neutral base and in the base-collector junction (the retrograde Ge profile). Similar results (f/sub T/=30 GHz) were achieved for both polysilicon emitter and single-crystal emitter PNP transistors with the same Ge retrograde profile. The position of the retrograde Ge profile in the base-collector junction was controlled by a self-aligned channeled boron implant through the SiGe base. Numerical simulations demonstrate that the peak f/sub T/ is very sensitive to the retrograde Ge position with respect to the base-collector doping profiles.<>
Keywords :
Ge-Si alloys; bipolar transistors; doping profiles; semiconductor materials; 30 GHz; AC performance; SiGe base pnp transistors; base profile; base-collector doping profiles; base-collector junction; polysilicon emitter; retrograde profile; self-aligned channelled implant; semiconductor materials; single-crystal emitter; valence band barrier; Boron; Doping profiles; Germanium silicon alloys; Implants; Numerical simulation; Silicon germanium;
Conference_Titel :
Electron Devices Meeting, 1990. IEDM '90. Technical Digest., International
Conference_Location :
San Francisco, CA, USA
DOI :
10.1109/IEDM.1990.237232
