Epitaxial Si/SiGe growth studies in view of novel logic devices using an alternative Ge precursor gas

/ Epitaxial Si/SiGe growth studies in view of novel logic devices using an alternative Ge precursor gas

Epitaxial Si/SiGe growth studies in view of novel logic devices using an alternative Ge precursor gas

Study chemical vapor deposition, SiGe material properties/characterization including the growth selectivity, impurity doping, and strain relaxation mechanisms

With the continuous evolution of logic devices,metal-oxide-semiconductor field effect transistors (MOSFET) have progressedfrom conventional planar architectures to three-dimensional (3D) structures, wherestacked horizontal channels, commonly referred to as nanosheets (NS), are usedto integrate p-type and n-type devices.

NS devices, as well as their vertical stackingin complementary field effect transistors (CFET), are now considered as the maindevice architecture for the most advanced technology nodes. In thisconfiguration, boron-doped Si 1-x Ge x (Si 1-x Ge x :B)and phosphorus-doped Si (Si:P) are used as p- and n-type source/drain (S/D) materials,respectively. These layers have to be grown exclusively on the exposed NSsidewalls, while avoiding growth on the surrounding masking materials, therebyachieving selective epitaxial growth (SEG). This selectivity is hence achieved bythe introduction of chlorine in the growth chemistry.

Chlorine-based precursors have emerged asparticularly promising candidates for enabling such selective growth. In thiscontext, GeCl 4 is considered as an attractive candidate to enablethe SEG of Si 1-x Ge x material. However, despite the commonusage of Si 1-x Ge x :B as a p-type S/D material, its growthusing GeCl 4 has received relatively limited attention. Inparticular, the influence of this alternative precursor on the boronincorporation and the resulting active dopant concentration in Si 1-x Ge x :BSEG is yet to be clarified.

Additionally, GeCl 4 is known toenable high growth rate of lowly-defective Si 1-x Ge x layers.Thereby, GeCl 4 also appears as a promising precursor to enable thickSi 1-x Ge x layers of high crystalline quality. Theinternship student will start with the growth of undoped Si 1-x Ge x layers using GeCl 4 to study chemical vapor deposition, Si 1-x Ge x material properties/characterization including the growth selectivity andstrain relaxation mechanisms. The study will be extended to Si 1-x Ge x :B selective growth . The candidate willbe introduced to several standard material characterization techniques likeXRD, XRR, micro-Hall effect, etc. The student willcontribute to the selective epitaxial growth studies of dopedmaterials byapplying the different characterization techniques.

Type of internship: Bachelor internship

Duration: 6 months

Required educational background: Materials Engineering, Physics

The reference code for this position is 2026-INT-267.

Only for self-supporting students.

Supervising scientist(s): For further information or for application, please contact Roger Loo ( Roger.Loo@imec.be ) and Thomas Dursap ( Thomas.Dursap@imec.be ) and Yosuke Shimura ( Yosuke.Shimura@imec.be )

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