Emitter and base fabrication in advanced bipolar transistors using gas immersion laser doping

Gas immersion laser doping (GILD) is presented as a promising new method to fabricate base and emitter regions of precise depth in advanced bipolar transistors. Two additional processes based on GILD technology are introduced: (1) ion implantation with laser redistribution, and (2) laser-induced recrystallization of deposited amorphous Si and Ge films. Transistors with 700-AA base width and maximum current gain of 100 are fabricated. Crystalline Si and Ge/sub 0.18/Si/sub 0.82/ layers are produced on Si<100> substrates using laser recrystallization. These laser-grown layers are suitable for device fabrication.<>