Selective Epitaxial Growth of In Situ Doped SiGe on Bulk Ge for p+/n Junction Formation

Electronics

Ali Asadollahi¹  Mikael Östling¹  Konstantinos Garidis¹  Ahmad Abedin¹  Per-Erik Hellström¹ 

[1] Division of Electronics and Embedded Systems, School of Electrical Engineering and Computer Science, KTH Royal Institute of Technology, 114 28 Stockholm, Sweden;

关键词: germanium;    SiGe;    junction;    diode;    selective;    epitaxy;   

DOI  :  10.3390/electronics9040578

来源: DOAJ

【 摘 要 】

Epitaxial in situ doped Si_0.73Ge_0.27 alloys were grown selectively on patterned bulk Ge and bulk Si wafers. Si_0.73Ge_0.27 layers with a surface roughness of less than 3 nm were demonstrated. Selectively grown p⁺Si_0.73Ge_0.27 layers exhibited a resistivity of 3.5 mΩcm at a dopant concentration of 2.5 × 10¹⁹ boron atoms/cm³. P⁺/n diodes were fabricated by selectively growing p⁺- Si_0.73Ge_0.27 on n-doped bulk Ge and n-doped Si wafers, respectively. The geometrical leakage current contribution shifts from the perimeter to the bulk as the diode sizes increase. Extracted near midgap activation energies are similar to p⁺/n Ge junctions formed by ion implantation. This indicates that the reverse leakage current in p⁺/n Ge diodes fabricated with various doping methods, could originate from the same trap-assisted mechanism. Working p⁺/n diodes on Ge bulk substrates displayed a reverse current density as low as 2.2·10⁻² A/cm² which was found to be comparable to other literature data. The layers developed in this work can be used as an alternative method to form p⁺/n junctions on Ge substrates, showing comparable junction leakage results to ion implantation approaches.

【 授权许可】

Unknown