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Charge Storage Mechanism of Drain Induced Dynamic Threshold Voltage Shift in ${p}$ -GaN Gate HEMTs.
- Source :
- IEEE Electron Device Letters; Apr2019, Vol. 40 Issue 4, p526-529, 4p
- Publication Year :
- 2019
-
Abstract
- The drain induced dynamic threshold voltage (${V}_{\textrm {th}}$) shift of a ${p}$ -GaN gate HEMT with a Schottky gate contact is investigated, and the underlying mechanisms are explained with a charge storage model. When the device experiences a high drain bias ${V}_{\textrm {DSQ}}$ , the gate-to-drain capacitance (${C}_{\textrm {GD}}$) is charged to ${Q}_{\textrm {GD}}$ (${V}_{\textrm {DSQ}}$). As the drain voltage drops to ${V}_{\textrm {DSM}}$ where ${V}_{\textrm {th}}$ is measured, ${C}_{\textrm {GD}}$ is expected to be discharged to ${Q}_{\textrm {GD}}$ (${V}_{\textrm {DSM}}$). However, the metal/ ${p}$ -GaN Schottky junction could block the discharging current, resulting in storage of negative charges in the ${p}$ -GaN layer. For the device to turn on, additional gate voltage is required to counteract the stored negative charges, resulting in a positive shift of ${V}_{\textrm {th}}$. The dynamic ${V}_{\textrm {th}}$ shift is an intrinsic and predictable characteristic of the ${p}$ -GaN gate HEMT which is linearly correlated with $\Delta \!{Q}_{\textrm {GD}}={Q}_{\textrm {GD}}$ (${V}_{\textrm {DSQ}}$) $- {Q}_{\textrm {GD}}$ (${V}_{\textrm {DSM}}$). The ${V}_{\textrm {th}}$ shift is dependent on ${V}_{\textrm {DSQ}}$ as well as ${V}_{\textrm {DSM}}$ , indicating that the ${V}_{\textrm {th}}$ shift is varying along the load line during a switching operation. [ABSTRACT FROM AUTHOR]
- Subjects :
- THRESHOLD voltage
ELECTRIC potential
GATES
STORAGE
ELECTRIC capacity
LOGIC circuits
Subjects
Details
- Language :
- English
- ISSN :
- 07413106
- Volume :
- 40
- Issue :
- 4
- Database :
- Complementary Index
- Journal :
- IEEE Electron Device Letters
- Publication Type :
- Academic Journal
- Accession number :
- 135773310
- Full Text :
- https://doi.org/10.1109/LED.2019.2900154