Lateral III/V HEMT Recombination Contact for Hole Diffusion Control
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Solution Overview
Problem
Lateral III/V heterostructure FETs with an n-channel and a p-type semiconductor between one of the load contacts and a proximate gate contact experience performance degradation due to trapping of conducting electrons, especially under fast switching and high electric fields.
Innovation Solution
A floating ohmic contact is introduced between the p-type semiconductor and the proximate gate contact, serving as a recombination zone for injected holes to counteract extended diffusion and accumulation, thereby enhancing the recombination of holes and improving device performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If p-type semiconductor is placed between load contact and gate contact to enable hole injection, then device control is improved, but dynamic resistance increases due to extended diffusion of injected holes
Solution Approach 1:
The floating ohmic contact serves as an intermediary recombination zone that captures holes before they can diffuse extensively into the channel region. This mediator structure allows controlled hole injection for device control while limiting the harmful extended diffusion that increases dynamic resistance.
Solution Approach 2:
The floating ohmic contact creates a localized recombination region with specific properties (high recombination efficiency) distinct from the gate contact region. This local quality enhancement ensures holes are recombined in a controlled manner at the floating contact, preventing them from affecting the channel conductivity and dynamic resistance.
2Duration of action of stationary object
If floating ohmic contact is introduced as recombination zone to reduce hole accumulation, then device lifetime is improved, but device complexity increases
Solution Approach 1:
The recombination function is extracted as a separate floating ohmic contact element, which simplifies the overall device design by dedicating a specific component to hole recombination. This extraction improves device lifetime by preventing hole accumulation without significantly complicating the device structure, as the floating contact can be integrated into existing contact patterns.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The implementation of a floating ohmic contact as a recombination zone improves the dynamic and static lifetimes of the FETs, reduces device failure due to hole accumulation, and mitigates avalanche-type transistor breakdowns.
Implementation Method 1
a floating ohmic contact between the p-type semiconductor and the proximate gate contact, namely as a recombination zone for the injected holes
Implementation Method 2
The p-type semiconductor is adapted for injecting holes into a portion of the transistor channel
Implementation Method 3
HEMT, namely the high electron mobility transistor. It is based on the high mobility of conducting electrons in the channel
Data Source
AI summary
The invention relates to a lateral field effect transistor, in particular a HEMT having a heterostructure, in a III/V semiconductor system with a p-type semiconductor being arranged between an ohmic load contact, in particular a drain contact, and a gate contact of the transistor for an injection of holes into a portion of the transistor channel. Further, a recombination zone implemented by a floating ohmic contact is provided for to improve the device performance.