Abstract
As the miniaturization of the size of semiconductor components, the silicon-based transistor has reached its material limitations, so that researching the new materials (silicon-germanium compound) to replace silicon is more important. The ion implantation technology is conducted to discuss the activation issue of p-type dopants, due to silicon-germanium epitaxial layer has the stress effect to enhance the carrier mobility, it is in a conflict of high-temperature annealing. In order to maintain the stress of the epitaxial silicon germanium layer and achieve the activation level of the carrier at the same time, this paper explores a new annealing method - microwave annealing (MWA) with the low thermal budget. In this study, we have investigated that using one-step microwave annealing energy in 3P (1P = 600W), which can make boron implanted into 30% Ge content of silicon germanium layer has the lowest sheet resistance (170 ohm/sq), the best epitaxial layer quality and the better residual stress index (1.48%). However, using two-step microwave annealing energy in 3P+1P over 100s, it can further achieve higher activation level for Si0.7Ge0.3: B sample without stress relaxation. (Sheet resistance as low as 134.6 ohm/sq, Hall measurement mobility of 302.7 cm2/Vs.).
Highlights
In scaling down the physical gate length of metal-oxidesemiconductor field effect transistors (MOSFETs) to 10/7 nm by 2017 to meet the roadmap of IMEC in 2015,1 several challenges must be overcome
We have investigated the activation ability and stress conservation of silicon-germanium layers with varies annealing methods
The results show that higher Ge content has the lower FWHM of XRD peak and stronger Si-Si bonding intensity, which confirm that more Ge atoms occupy the lattice cause stress effect
Summary
In scaling down the physical gate length of metal-oxidesemiconductor field effect transistors (MOSFETs) to 10/7 nm by 2017 to meet the roadmap of IMEC in 2015,1 several challenges must be overcome. To keep the junction and contact resistance low, high temperature anneals have been extensively studied to electrically activate implanted dopants and repair lattice damage created after ion implantation to reduce junction leakage currents. These high temperature-annealing methods have demonstrated some successful applications to the source/drain anneal, they all still have a number of problems that make processing more complicated. High current and low energy ion implantation and low-temperature microwave annealing were employed to achieve ultra-shallow junction and conserve the elastics train in the SiGe layer. Unlike traditional thermal annealing which requires higher energy to activate the dopant, a 300W∼600W microwave was used to achieve low sheet resistance
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