CN-122028495-A - GaN HEMT power device with diode regulation and control substrate voltage

CN122028495ACN 122028495 ACN122028495 ACN 122028495ACN-122028495-A

Abstract

The invention belongs to the technical field of power semiconductors, and discloses a GaN HEMT power device with a diode for regulating and controlling substrate voltage, wherein the substrate is connected with a field plate, and a diode is connected between the diode and the ground, and an isolation region is arranged between the drain electrode and the diode region, wherein the anode of the diode is grounded, and the cathode of the diode is connected with the substrate. When the device is in a blocking state, the isolation region prevents the high-voltage drain from transversely penetrating into the diode region, the substrate is still in high potential to assist in exhausting the drift region, and meanwhile net negative charges can be accumulated on the substrate, when the device is in a conducting state, the substrate potential is clamped to the conducting voltage of the diode, and meanwhile a release passage is provided for the net negative charges accumulated on the substrate, so that the quick release of charges is promoted, and the degradation of dynamic on-resistance is restrained. The invention has the advantages of keeping high voltage resistance of the device, inhibiting dynamic on-resistance degradation, improving the stability of the device, having simple structure and being compatible with the conventional process.

Inventors

YANG KEMENG
CHEN JING
LI MAN
ZHANG MAOLIN
FAN ZHIBO
PAN HAOYU
ZHANG LINGYUN
GAO LIYAN
ZHANG JUN
GUO YUFENG
YAO JIAFEI
CHEN HANG

Assignees

南京邮电大学
南京邮电大学南通研究院有限公司

Dates

Publication Date: 20260512
Application Date: 20260213

Claims (6)

1. A GaN HEMT power device with diode regulation substrate voltage comprises a substrate (1), a GaN buffer layer (2), a GaN channel layer (3), an AlGaN barrier layer (4), a passivation layer (7) and a floating field plate structure (8) which are sequentially stacked from bottom to top along the vertical direction of the device, wherein a first conductive material (61), a grid structure, a third conductive material (63), a fourth conductive material (64) and a fifth conductive material (65) which are not mutually contacted are sequentially arranged on the surface of the device from one side to the other side along the transverse direction of the device, the lower end of the first conductive material (61) penetrates through the passivation layer (7) to be in contact with the barrier layer (4), the contact is ohmic contact, the upper surface of the first conductive material (61) is led out of a source electrode, the source electrode is grounded, the lower end of the third conductive material (63) penetrates through the passivation layer (7) to be in contact with the barrier layer (4), the contact is ohmic contact, the upper surface of the third conductive material (63) is led out of a drain electrode, the fourth conductive material (64) penetrates through the barrier layer (4) to be in contact with the upper surface of the channel layer (3), the lower end of the fourth conductive material (64) penetrates through the passivation layer (4) to be in contact with the upper surface of the barrier layer (4), the fifth conductive material (62) is in contact with the upper surface of the barrier layer (4) and the upper surface of the second conductive material (5), a grid electrode is led out from the upper surface of the second conductive material (62); The semiconductor device is characterized in that an isolation region (11) is arranged between the third conductive material (63) and the fourth conductive material (64), and the isolation region (11) extends to the surface of the substrate (1) along the vertical direction; The substrate (1) is connected with the floating field plate structure (8) through a first metal (9), a diode is connected between the substrate (1) and the ground, a diode cathode is led out of the upper surface of the fourth conductive material (64), the diode cathode is connected with the substrate (1) through the first metal (9), the contact between the fifth conductive material (65) and the channel layer (3) is Schottky contact, a diode anode is led out of the upper surface of the fifth conductive material (65), and the diode anode is connected with the source through a second metal (10).
2. The GaN HEMT power device with the diode regulated substrate voltage according to claim 1, wherein the diode is a PN junction diode, the PN junction diode includes a second P-type GaN layer (12) disposed below the fifth conductive material (65), the P-type GaN layer (12) forms a PN junction with the AlGaN barrier layer (4) and the GaN channel layer (3), the fifth conductive material (65) forms an ohmic contact with the second P-type GaN layer (12), and an anode of the diode is led out from an upper surface of the fifth conductive material (65).
3. The GaN HEMT power device with diode steering substrate voltage of claim 1, wherein the first conductive material (61) and the third conductive material (63) lower ends penetrate the barrier layer (4) and extend into the GaN channel layer (3), and the lower surface forms ohmic contact with the GaN channel layer (3).
4. A GaN HEMT power device with diode steering substrate voltage according to claim 1, characterized in that the isolation region (11) is an ion implantation isolation or trench isolation.
5. The GaN HEMT power device with diode steering substrate voltage of claim 4, wherein said isolation region (11) is isolated by a trench and the isolation region (11) is filled with a passivation layer (7).
6. The GaN HEMT power device with diode steering substrate voltage of claim 1, wherein the substrate (1) material is silicon, silicon carbide, sapphire or GaN.

Description

GaN HEMT power device with diode regulation and control substrate voltage Technical Field The invention belongs to the technical field of power semiconductors, and relates to a GaN HEMT power device with a diode for regulating and controlling substrate voltage. Background The third generation wide bandgap semiconductor GaN has the advantages of wide bandgap, high critical breakdown field strength, high electron mobility and the like, and is suitable for high-power and high-frequency devices. The conventional GaN HEMT power device forms high-density two-dimensional electron gas (2 DEG) through spontaneous polarization and piezoelectric polarization effects, so that lower on-resistance and higher current density are obtained. However, in high voltage switching applications, gaN HEMT power devices are typically subjected to higher drain voltages in the off state, causing buffer layer traps to trap electrons, especially if the substrate is at a high potential, which is more prone to trap electrons and accumulate a net negative charge on the substrate. When the device is switched from the off state to the on state, charges accumulated in the substrate and the buffer layer are difficult to release, so that the dynamic on-resistance is degraded, and the switching stability and reliability of the device are reduced. Although Li et al in the 900V normal-OFF GaN-on-Si Transistors Achieved by Substrate Potential Modulation (SPM) document propose modulating the substrate potential by integrating a main transistor with a substrate-connected MOS transistor, achieving high withstand voltage and suppressing dynamic resistance degradation. However, the MOS tube integrated by the structure can increase the input capacitance of the grid electrode of the device and increase the load loss of the grid electrode driving circuit. Patent application CN119835964a discloses a GaN HMET power device with substrate voltage regulation, which is connected with floating field plate metal through a substrate, and uses high potential of a field plate under high drain to raise substrate potential, so as to assist in exhausting drift region without increasing driving loss, and raise device withstand voltage, but the improvement of substrate potential in the structure can cause the substrate to accumulate negative charge, thereby causing dynamic resistance degradation problem. Disclosure of Invention Aiming at the problems, the invention provides a GaN HEMT power device with a diode for regulating and controlling the substrate voltage, which realizes substrate clamping by connecting a diode between a substrate and ground, keeps high withstand voltage, simultaneously suppresses dynamic on-resistance degradation, improves the switching stability, has a simple structure and is compatible with a process. The GaN HEMT power device with the diode regulating substrate voltage comprises a substrate, a GaN buffer layer, a GaN channel layer, an AlGaN barrier layer, a passivation layer and a floating field plate structure which are sequentially laminated from bottom to top along the vertical direction of the device; the device comprises a passivation layer, a first conductive material, a gate structure, a third conductive material, a fourth conductive material and a fifth conductive material, wherein the first conductive material, the gate structure, the third conductive material, the fourth conductive material and the fifth conductive material are not in contact with each other in sequence from one side to the other side along the transverse direction of the device, the lower end of the first conductive material penetrates through the passivation layer to be in ohmic contact with the barrier layer, the upper surface of the first conductive material is led out of a source electrode, the source electrode is grounded, the lower end of the third conductive material penetrates through the passivation layer to be in contact with the barrier layer, the contact of the passivation layer is ohmic contact with the upper surface of the third conductive material, the fourth conductive material penetrates through the barrier layer to be in ohmic contact with the upper surface of the channel layer, the fifth conductive material penetrates through the barrier layer to be in contact with the upper surface of the channel layer, the contact of the fifth conductive material is Schottky contact; The isolation region extends to the surface of the substrate along the vertical direction, the substrate is connected with the floating field plate structure through the first metal, a diode is connected between the substrate and the ground, a diode cathode is led out of the upper surface of the fourth conductive material, the diode cathode is connected with the substrate through the first metal, a diode anode is led out of the upper surface of the fifth conductive material, and the diode anode is connected with the source through the second metal. Further, the diode is a PN junction