Record Breakdown Voltage (2200 V) of GaN DHFETs on Si With 2- Buffer Thickness by Local Substrate Removal

In this letter, we present a local substrate removal technology (under the source-to-drain region), reminiscent of through-silicon vias and report on the highest ever achieved breakdown voltage(VBD)of AlGaN/GaN/AlGaN double-heterostructure FETs on a Si (111) substrate with only 2--thick AlGaN buffer. Before local Si removal,VBDsaturates at~700 V at a gate–drain distance(LGD) ≥ 8\. However, after etching away the substrate locally, we measure a recordVBDof 2200 V for the devices withLGD = 20\. Moreover, from Hall measurements, we conclude that the local substrate removal integration approach has no impact on the 2-D electron gas channel properties.