Publication details
Control of metal ion acceleration via gas rarefaction in synchronized HiPIMS for improved epitaxial AlN growth
| Authors | |
|---|---|
| Year of publication | 2026 |
| Type | Peer-reviewed scientific article |
| Magazine / Source | SURFACE AND COATINGS TECHNOLOGY |
| MU Faculty or unit | |
| Citation | |
| web | https://www.sciencedirect.com/science/article/pii/S0257897226005761 |
| Doi | https://doi.org/10.1016/j.surfcoat.2026.133724 |
| Keywords | HiPIMS; AlN; Epitaxial growth; Gas rarefaction; Ion flux dynamics; Bias synchronization |
| Attached files | |
| Description | Epitaxial growth of AlN on silicon is highly attractive for integrated nitride-based devices but remains challenging, as conventional techniques typically require high growth temperatures or suffer from limited industrial scalability. High-power impulse magnetron sputtering (HiPIMS) has emerged as a promising alternative by enabling enhanced ionization of the sputtered species and control of ion energy through substrate biasing. However, selective acceleration of the ionized film-forming species in HiPIMS is particularly challenging for AlN, due to the low atomic mass of Al relative to Ar. In this work, we successfully demonstrate that selective Al+ ion acceleration can be achieved by tuning the HiPIMS pulse length to exploit gas rarefaction, which suppresses Ar+ ion generation while sustaining a high Al+ ion density. Time-resolved mass spectrometry, supported by process modeling, reveals that increasing the pulse length induces a pronounced temporal separation between Ar+ and Al+ ion fluxes, resulting in a metal-ion–rich time window suitable for synchronized substrate biasing. Under these conditions, epitaxial AlN growth on Si(111) is achieved at a substantially reduced substrate temperature without the use of buffer or seed layers. The resulting films exhibit a clear enhancement in crystalline quality, strain state, and surface morphology consistent with a shift from Ar-ion–dominated to metal-ion–assisted growth. These findings establish pulse-length–controlled HiPIMS as an effective strategy for metal-ion–assisted epitaxial growth of AlN on silicon at moderate temperatures. |