Germanium Junctions for Beyond-Si Node Using Flash Lamp Annealing (FLA)
- PDF / 812,722 Bytes
- 6 Pages / 612 x 792 pts (letter) Page_size
- 4 Downloads / 223 Views
Germanium Junctions for Beyond-Si Node Using Flash Lamp Annealing (FLA) H. Tanimura1, H. Kawarazaki1, K. Fuse1, M. Abe1, Y. Ito1, T. Aoyama1, S. Kato1, I. Kobayashi1, T. Nagayama2, N. Hamamoto2, S. Sakai2 1 SCREEN Semiconductor Solutions Co., Ltd. 480-1 Takamiya-cho, Hikone, Shiga, 522-0292 Japan 2 Nissin Ion Equipment Co., Ltd. 575 Kuze-Tonoshiro-cho, Minami-ku, Kyoto, 601-8205 Japan ABSTRACT We report on the formation of shallow junctions with high activation in both n+/p and p+/n Ge junctions using ion implantation and Flash Lamp Annealing (FLA). The shallowest junction depths (Xj) formed for the n+/p and p+/n junctions were 7.6 nm and 6.1 nm with sheet resistances (Rs) of 860 ohms/sq. and 704 ohms/sq., respectively. By reducing knocked-on oxygen during ion implantation in the n+/p junctions, Rs was decreased by between 5% and 15%. The lowest Rs observed was 235 ohms/sq. with a junction depth of 21.5 nm. Hall measurements clearly revealed that knocked-on oxygen degraded phosphorus activation (carrier concentration). In the p+/n Ge junctions, we show that ion implantation damage induced high boron activation. Using this technique, Rs can be reduced from 475 ohms/sq. to 349 ohms/sq. These results indicate that the potential for forming ultra-shallow n+/p and p+/n junctions in the nanometer range in Ge devices using FLA is very high, leading to realistic monolithically-integrated Ge CMOS devices that can take us beyond Si technology. INTRODUCTION The high carrier mobility of Ge makes it one of the most promising materials for ultralow-power, high-performance MOSFETs. However, there are challenges in fabricating both the n+/p and p+/n junctions. In n-type junctions, it is difficult to form highly activated shallow junctions due to the low solid solubility and high diffusivity [1]. In contrast, it is easy to form shallow p+/n junctions, but higher activation is required for higher performance. In this context, we have reported some progress in the formation of both n+/p and p+/n Ge junctions, especially in diffusion control and with methods to enhance the dopant activation, using a FLA tool [2, 3]. In this paper, we summarize the progress and discuss this with new data related to the mobility and carrier concentration in Ge junctions. EXPERIMENT P-type and n-type Ge wafers were cleaned with de-ionized water. Then, phosphorus (P) or boron (B) was implanted with an EXCEED®3000 or CLARIS, manufactured by Nissin Ion Equipment Co., Ltd. Some samples were given a Pre-Amorphization Implant (PAI) using Ge ions. After ion implantation, the samples were annealed using FLA equipment made by SCREEN Semiconductor Solutions Co., Ltd. The feature parameter of our FLA is a widely variable flash pulse in the millisecond range [2, 3]. With the FLA tool it is easy to adjust the time with sub-millisecond resolution, change the ramp up rate and the gas ambient, and so on, enabling us to meet the various demands. For these evaluations, we used a 1.4ms short pulse. The peak temperature (Tp) used was from 590 to 800oC.
Downloaded from https
Data Loading...
